Project Support => Support => Topic started by: D.M. on July 03, 2024, 03:51:11 am
Title: Setting up SMTP Mailing service
Post by: D.M. on July 03, 2024, 03:51:11 am
Hello there community ! Our forums I am currently working on is just about finished and ready to be open and running, but sadly I am hitting a wall when it comes to SMTP integration, namely I have chosen the SendGrid SMTP service which has a good enough free plan for a low monthly email load but it doesn't seem to be working. Everything is setup in the backend verified my domain at SendGrid, updated the DNS records on my backend even though I have tried all sorts of combinations in the ''SMTP Client'' , ''Proxy'' and ''STARTTLS'' fields I am stuck and not getting any emails through, should the STARTTLS even be checked when going through an SSL proxy and domain?, tried entering the non-ssl proxies which are given being two numbers separated by commas '','' but it gives me a strange error and deletes the mail queue. Maybe I should try another service provider or ? The only mails I have successfully sent were through PHP and those get fed into the spam folder as we all know, so theres no point in going for PHP
If anyone has any suggestions on what I may be doing wrong It would mean a lot ! Thanks in advance!
EDIT: Just to note that the problem is occurring definitely at the ElkArte backend, I've got mail queue turned on just in case and when I click to send the mail queue it just refreshes the page and the time of the email but it doesnt let it go through
This is the error code from the error log:
eaea1ba6e0m2C0drhqPd9mzoFbJTNnsN Type of error: General Could not connect to SMTP host: 110 : Connection timed out
EDIT: I have since then been able to get through with the port 25, this is the new error I am getting (Keep in mind that I have tried every single domain / sender name combination including leaving it blank for the system to detect it, also verified both single sender and domain identities)
KqLWv938qwWMgz1g8YJOFtJ5Djqh4HTV Type of error: General Ran into problems sending Mail. Error: 550 The from address does not match a verified Sender Identity. Mail cannot be sent until this error is resolved. Visit https://sendgrid.com/docs/for-developers/sending-email/sender-identity/ to see the Sender Identity requirements
EDIT: Currently waiting on new DNS changes to take effect
Title: Re: Setting up SMTP Mailing service
Post by: Steeley on July 03, 2024, 11:38:25 am
Quote from: Denis M. – Type of error: General Ran into problems sending Mail. Error: 550 The from address does not match a verified Sender Identity. Mail cannot be sent until this error is resolved. Visit https://sendgrid.com/docs/for-developers/sending-email/sender-identity/ to see the Sender Identity requirements
EDIT: Currently waiting on new DNS changes to take effect
Typically, the server that hosts your forum (https://www.mydomain.com/myforum), also has a mailserver, so the simplest is to establish an email account on mydomain for your forum (myforum@mydomain.com). Most mail security protocols now require that the myforum@mydomain.com account only allows authentication from myforum@mydomain.com, not some other addy (such as "admin@mydomain.com"), trying to send through it.
Sendgrid has to pretend it's your server's mailserver, meaning you probably need to have domain authentication, and you need an individual account for each forum email address sending mail. (I used to be able to have one primary sending account - master@mydomain.com- but now the from addy, and maybe the replyto addy? - has to match the account, not just log in as "master@mydomain.com, password: "pw1230hmy". The mailserver sets those rules and YMMV (your mileage may vary)..
For sanity, you also need an individual account for each addy receiving email (not redirects to a common addy), if ElkArte needs to retrieve and direct them to a particular function (such as postbymail to particular forum categories).
Ports may also be important - my receiving ports need to use port 995, my sending ports need to use port 465. I also use Direct SSL, but not STARTTLS. But that is determined by my host's mailserver requirements. Port 25, for example is basic old/school SMTP and has little security support, so few mailservers support port 25 any more..
I'd need to know a lot more about your forum configuration and sendgrid in order to be more specific, but the first thing I'd explore is whether your host has email account support for your forum - if so, that simplifies things greatly..
Title: Re: Setting up SMTP Mailing service
Post by: Spuds on July 03, 2024, 11:40:21 am
I've only run SMTP on my localhost, and no I am not suggesting you run your own mailserver (unless you like great and lasting pain), I'm only indicating I'm a noob on this one. Having only glanced at the sendgrid docs ....
SMTP Server looks like smtp.sendgrid.net should be entered SMTP Client not sure, but normally this is the domain name of your site, like elkarte.net SMTP Port looks like sendgrid uses 465 START TLS probably should be checked Username from your sendgrid credentials Password again from your sendgrid credentials
ETA: Typed the above while @Steeley was giving you better information above
Title: Re: Setting up SMTP Mailing service
Post by: D.M. on July 03, 2024, 02:23:21 pm
Quote from: Denis M. – Type of error: General Ran into problems sending Mail. Error: 550 The from address does not match a verified Sender Identity. Mail cannot be sent until this error is resolved. Visit https://sendgrid.com/docs/for-developers/sending-email/sender-identity/ to see the Sender Identity requirements
EDIT: Currently waiting on new DNS changes to take effect
Typically, the server that hosts your forum (https://www.mydomain.com/myforum), also has a mailserver, so the simplest is to establish an email account on mydomain for your forum (myforum@mydomain.com). Most mail security protocols now require that the myforum@mydomain.com account only allows authentication from myforum@mydomain.com, not some other addy (such as "admin@mydomain.com"), trying to send through it.
Sendgrid has to pretend it's your server's mailserver, meaning you probably need to have domain authentication, and you need an individual account for each forum email address sending mail. (I used to be able to have one primary sending account - master@mydomain.com- but now the from addy, and maybe the replyto addy? - has to match the account, not just log in as "master@mydomain.com, password: "pw1230hmy". The mailserver sets those rules and YMMV (your mileage may vary)..
For sanity, you also need an individual account for each addy receiving email (not redirects to a common addy), if ElkArte needs to retrieve and direct them to a particular function (such as postbymail to particular forum categories).
Ports may also be important - my receiving ports need to use port 995, my sending ports need to use port 465. I also use Direct SSL, but not STARTTLS. But that is determined by my host's mailserver requirements. Port 25, for example is basic old/school SMTP and has little security support, so few mailservers support port 25 any more..
I'd need to know a lot more about your forum configuration and sendgrid in order to be more specific, but the first thing I'd explore is whether your host has email account support for your forum - if so, that simplifies things greatly..
Quote from: Spuds – I've only run SMTP on my localhost, and no I am not suggesting you run your own mailserver (unless you like great and lasting pain), I'm only indicating I'm a noob on this one. Having only glanced at the sendgrid docs ....
SMTP Server looks like smtp.sendgrid.net should be entered SMTP Client not sure, but normally this is the domain name of your site, like elkarte.net SMTP Port looks like sendgrid uses 465 START TLS probably should be checked Username from your sendgrid credentials Password again from your sendgrid credentials
ETA: Typed the above while @Steeley was giving you better information above
Thanks gentlemen ! Although you are very informed and gave me a lot of useful information I will still be waiting a bit longer for the DNS records to update correctly (Though sendgrid Verify option has checked them and confirmed they are added)
While I wait here's some additional information about my current project / sendgrid details:
I am using a subdomain for the forums currently eg. forums.mydomain.cc SendGrid verified my subdomain and gave me a new domain name that I thought was the correct client id eg. em111.forums.mydomain.cc When I set up port 465 the error pops up: ''Could not connect to SMTP host: 110 : Connection timed out'' Only when using port 25 I get the: ''Type of error: General Ran into problems sending Mail. Error: 550 The from address does not match a verified Sender Identity. Mail cannot be sent until this error is resolved. Visit https://sendgrid.com/docs/for-developers/sending-email/sender-identity/ to see the Sender Identity requirements'' <- Even though I have tried every single combination regarding the client ID eg. forums.mydomain.cc , em111.forums.mydomain.cc , admin@forums.mydomain.cc , admin@mydomain.cc , when left blank the system fills it up with my hosting provider nameserver
I have verified the Sender Identification and passed the process as well as the domain verification, only thing that I could think of being wrong is the DNS records not updating yet eg. 48 hours, but i doubt it since SendGrid verified my domain and the updated records or may this be the cause ?
Thanks in advance any information helps !
EDIT: Also the question is should I verify my main domain on sendgrid as my domain or the actual forums.mydomain.cc subdomain I'm basically thinking of everything ATM and what could be the issue , currently verified forums.mydomain.cc and it's not working btw
Title: Re: Setting up SMTP Mailing service
Post by: Spuds on July 04, 2024, 10:20:34 am
I tried to signup for a free account to help debug, but it was rejected for some reason LOL ... after it confirmed my email and 2FA to my phone.
Anyway looking at the help page
- Looks like the TLS port is on 587 and not the standard 465 ... so check TLS and use port 587 - Userid may need to be YXBpa2V5 which is a base64 version for the string apikey - Password appears to be your base64 encoded apikey ( you can use https://www.base64encode.org ) to encode your key
Really have no idea if that will work, just spit balling here
Title: Re: Setting up SMTP Mailing service
Post by: D.M. on July 04, 2024, 12:48:25 pm
Quote from: Spuds – I tried to signup for a free account to help debug, but it was rejected for some reason LOL ... after it confirmed my email and 2FA to my phone.
Anyway looking at the help page
- Looks like the TLS port is on 587 and not the standard 465 ... so check TLS and use port 587 - Userid may need to be YXBpa2V5 which is a base64 version for the string apikey - Password appears to be your base64 encoded apikey ( you can use https://www.base64encode.org ) to encode your key
Really have no idea if that will work, just spit balling here
Ah thanks for the info Spuds but that gives me a different error: 0aspXWPuM8gCeWQH29SAedME8v9naYZD Type of error: General Ran into problems sending Mail. Error: 535 Authentication failed: Bad username / password
Seems like the only problem is the client ID / sender identity, still getting that error while on port 587 , although port 465 wont even go through , I've contacted my hosting support team for additional information waiting for them to reply by email since they took the holidays off on the livechat support
Title: Re: Setting up SMTP Mailing service
Post by: Spuds on July 04, 2024, 01:52:45 pm
So at least its connecting now .... continue to use 587 and TLS
Do you have other credentials you can enter? Try putting back what you had.
Title: Re: Setting up SMTP Mailing service
Post by: D.M. on July 05, 2024, 06:11:58 am
Quote from: Spuds – So at least its connecting now .... continue to use 587 and TLS
Do you have other credentials you can enter? Try putting back what you had.
The credentials for Username and Password are: Username: apikey Password: (the api key)
Those work, but it seems that there's a problem with the ClientID field , I am not exactly sure which domain/email address should be entered, even though I tried all possible combinations supplied by SendGrid, I also got a reply from my hosting provider service staff that I should re-check DNS records and email validity gonna be doing that today since the 48h of DNS changes expires today, they also suggested I contact SendGrid support so I will be doing that also
Thanks for the brainstorming Spuds !
Title: Re: Setting up SMTP Mailing service
Post by: ahrasis on July 05, 2024, 07:48:58 am
Quote from: Spuds – SMTP Client not sure, but normally this is the domain name of your site, like elkarte.net
Agreed. By the way, it has explanation if one clicked the question mark to understand more.
Quote? A little lost? Let me explain: Used to identify this client to the SMTP server. The field should contain the fully-qualified domain name (FQDN) of the SMTP client. In situations in which the client system does not have a meaningful domain name you can instead use an address literal formatted as [ipv4] or [IPv6:ipv6 address]. If left blank the system will attempt to detect this value for you.
Hope that helps.
Title: Re: Setting up SMTP Mailing service
Post by: D.M. on July 06, 2024, 06:45:12 am
Quote from: Spuds – SMTP Client not sure, but normally this is the domain name of your site, like elkarte.net
Agreed. By the way, it has explanation if one clicked the question mark to understand more.
Quote? A little lost? Let me explain: Used to identify this client to the SMTP server. The field should contain the fully-qualified domain name (FQDN) of the SMTP client. In situations in which the client system does not have a meaningful domain name you can instead use an address literal formatted as [ipv4] or [IPv6:ipv6 address]. If left blank the system will attempt to detect this value for you.
Hope that helps.
Greetings Ahrasis ! Yes that is correct information, and I have surely followed every single written guide on resolving the issue that pops up, but after contacting SendGrid support it seems that the problem still persists regarding their authentication system, I have already authenticated and verified my domain which causes email addresses to get authenticated automatically although the support staff told me that I still do not have a valid authenticated Email address which is capable of going through the mailing system, I am now currently in the process of fixing that issue with the help of SendGrid support and I will be sure to update this topic with the results and resolved issue !
Title: Re: Setting up SMTP Mailing service
Post by: Spuds on July 08, 2024, 08:29:42 am
Quote from: Denis M. – I will be sure to update this topic with the results and resolved issue !
Looking forward to the resolution, very curious :smiley:
Title: Re: Setting up SMTP Mailing service
Post by: D.M. on July 09, 2024, 02:01:25 pm
Greetings to everyone ! I am happy to say that the issue has now been resolved finally ! After talking with SendGrid support for a couple of days we were finally able to verify the error after they looked into their backend error logs!
The issue was caused by verifying my subdomain which was a mistake ! After verifying my main domain instead of the subdomain the email finally went through !
My domain is now verified and capable to send SMTP mail!
Let this be a guide for future encounters people may have ! Be sure to verify your main domain since SendGrid services can not verify subdomains as a sender identity!
Cheers and good luck ! :partying_face :partying_face
We may get confused of this some times since both could be FQDN, so that is good to know.
Another question, did you also try to leave it blank instead of filling it and did that work?
The funny thing is that my ''SMTP Client'' field is actually setup wrong and it's still working ! I have my email address customaddress@forums.mydomain.cc in there but it still sends it through from the admin@forums.mydomain.cc email address so that's a bit funny if I understand correctly a domain name should be in there :laugh: but I guess I'll need to delete the admin@forums.mydomain.cc address from the SendGrid verified senders dashboard, but I'm currently too happy that it actually works and wont be touching anything so I don't ruin this happy feeling I got, well at least until I get a separate domain setup for the forums :cheesy:
I actually just verified my main domain ''mydomain.cc'' in the SendGrid backend and it went through, didn't even notice the SMTP Client field was wrong, I'm not sure how this is working but as they say ''Do not question happiness'' :laugh:
Title: Re: Setting up SMTP Mailing service
Post by: Steeley on July 10, 2024, 08:57:21 pm
Keep your notes, because at some point when it stops working, you'll want to get things configured "correctly" to be sure the problem isn't related to the "misconfiguration" that is "working anyway" at the moment..
Title: Re: Setting up SMTP Mailing service
Post by: D.M. on July 14, 2024, 02:17:46 pm
Quote from: Steeley – Keep your notes, because at some point when it stops working, you'll want to get things configured "correctly" to be sure the problem isn't related to the "misconfiguration" that is "working anyway" at the moment..
Got it ! Thanks for the heads up ! :sweat:
Title: Re: Setting up SMTP Mailing service
Post by: D.M. on July 15, 2024, 11:54:35 am
Well, my happiness was shortlasting ! @Steeley was right , it doesnt work, now theres a new error but I think it's hosting related , I have no idea how the first mail even went through and how this error just popped up out of nowhere without changing anything in the smtp :cry: :cry: :cry: :cry:
stream_socket_enable_crypto(): Peer certificate CN=`s7.webhostingsrbija.rs' did not match expected CN=`smtp.sendgrid.net'
This is what Chat GPT has to say: Understanding the Error stream_socket_enable_crypto(): This PHP function enables encryption on a stream, typically for securing communications with SSL/TLS. Peer certificate CN='s7.webhostingsrbija.rs': The Common Name (CN) in the SSL/TLS certificate presented by the SMTP server is s7.webhostingsrbija.rs. did not match expected CN='smtp.sendgrid.net': The script expects the Common Name to be smtp.sendgrid.net, which means your ElkArte forum is configured to connect to SendGrid’s SMTP server, but the server it’s actually connecting to is presenting a certificate for s7.webhostingsrbija.rs. Potential Causes Misconfigured SMTP Settings: Your ElkArte forum might be configured with incorrect SMTP server details. Man-in-the-Middle (MITM) Attack: While less likely, a MITM attack could be intercepting your SMTP connections and presenting a different certificate. Proxy or Intermediate Server: Your hosting provider might be routing SMTP connections through an intermediate server which presents its own certificate.
If he's using sendgrid as his email server, I don't think that (cpanel smtp filtering thing) is going to help him @ahrasis
@Denis M. - first, let me ask what is wrong with using your own host's email system (why are you messing with sendgrid at all)?
(FWIW, that error is saying the security certificates are not OAUTH2 (I suspect) security compliant. But, why you are involving ChatGPT in this is beyond me.. let's get back to basic SMTP stuff, which still works in most everywhere, and start there.. )
Title: Re: Setting up SMTP Mailing service
Post by: ahrasis on July 16, 2024, 01:53:09 am
Did you read or not? Because the problem (which is mentioned just above the said answer) is exactly the same:
Quote from: https://stackoverflow.com/q/41554028We are attempting to send an autoresponder email to new members. We're using the same configuration on other sites on the same server with no issue. Upon sending the email the following error is returned:
Quotestream_socket_enable_crypto(): Peer certificate CN=cs723.mojohost.com did not match expected CN=smtp.sendgrid.net
Title: Re: Setting up SMTP Mailing service
Post by: D.M. on July 16, 2024, 08:08:15 am
If he's using sendgrid as his email server, I don't think that (cpanel smtp filtering thing) is going to help him @ahrasis
@Denis M. - first, let me ask what is wrong with using your own host's email system (why are you messing with sendgrid at all)?
(FWIW, that error is saying the security certificates are not OAUTH2 (I suspect) security compliant. But, why you are involving ChatGPT in this is beyond me.. let's get back to basic SMTP stuff, which still works in most everywhere, and start there.. )
I want to use SendGrid because going through PHP just shoves the email into the spam folder, I need an SMTP setup since my hosting provider only supports registration/login/password reset emails and not ''You have a new reply on your post'' etc then they block your account
Quote from: ahrasis – Did you read or not? Because the problem (which is mentioned just above the said answer) is exactly the same:
Quote from: https://stackoverflow.com/q/41554028We are attempting to send an autoresponder email to new members. We're using the same configuration on other sites on the same server with no issue. Upon sending the email the following error is returned:
Quotestream_socket_enable_crypto(): Peer certificate CN=cs723.mojohost.com did not match expected CN=smtp.sendgrid.net
@Steeley @ahrasis It WORKED !
Just to update everyone that the problem was in the WHM settings (Cpanel) keep in mind I did not have access to those settings and I needed my hosting providers support to disable the ''SMTP Restrictions''
Though the email system is now working although theres a new problem regarding the email templates I will be posting a new topic about the issue
Thanks for all the help and support gentlemen, it means a lot !
Title: Re: Setting up SMTP Mailing service
Post by: Steeley on July 16, 2024, 03:12:25 pm
QuoteI needed my hosting providers support to disable the ''SMTP Restrictions''
Ummmm... ok, however, it looks like you are using Sendgrid in addition to your hosts email server, which is redundant - and accomplishes little while doubling your failure exposure .. since you still had to have your host do some configuration anyway, right?
QuoteI want to use SendGrid because going through PHP just shoves the email into the spam folder, I need an SMTP setup since my hosting provider only supports registration/login/password reset emails and not ''You have a new reply on your post'' etc then they block your account
OK, now you have cornfused me greatly..
Let's look a little closer and dispel some of that confusion..
When mail is received by your host's email system, it just puts that email in the account incoming mail folder.... (in the image below there's 4 email accounts, forumtest@.., <blank>_forum@.., <blank>-forum@.., webmaster@..,). Folder "new" is the incoming mail folder for the <blank>_forum@.., addy below)
(Link-10734 ) . . . What happens to those emails after that is strictly up to whatever email processing is done on your end.. be it a client provided by your host ("webmail interface") or your own software client (outlook, ms mail, Pegasus Mail, etc..) or ElkArte's own software routine, and/or cron jobs. It doesn't automatically just jump into a "spam folder". (If you notice, there IS no spam folder since neither I nor my host has enabled spam filtering)
Quote ..PHP just shoves the email into the spam folder,
I'm not sure what spam folder you are referring to, but if it doesn't happen with email through SendGrid, but does using your host, that is your host's software doing something it shouldn't after the email is received, and that just needs to be disabled or fixed.. (if it isn't already!)
[If you were to look at one of those files it looks "exactly" like the "raw view" of the email envelope you would see if you selected that view rather than the "prettied up" view of the email you would see that is done by your email client, to show you just the sender, subject, date received, and content. The client software decides what to do and how to do it based upon its configuration and what it finds in the contents of that email file. Likewise, ElkArte does it's own thing with email in whatever "folder" it is expecting email to reside in, based on EA's mail-handling configuration and what it finds in the account incoming email folder, in exactly the same way. It's not complicated (unless you make it so..) ]
The only reason I can see to use Sendgrid is if (a) you're going to be sending massive amounts of bulk emails that your host doesn't want to allow, or (b) your host is not co-operative/responsive to your mail configuration needs. (And your "Email Template" problem that you posted shows us why even that isn't a good reason to use Sendgrid.)
If it's the later reason (b), you'll be better off in the long run with a new host.. but it sounds like your host IS responsive ..
QuoteI needed my hosting providers support to disable the ''SMTP Restrictions''
...and apparently he did, and therefore he was... right?
I'm a big fan of "KISS" ... the fewer things that can go wrong, will usually result in fewer things going wrong. Redundancy doubles failure exposure and only improves reliability if the redundancy is in parallel - it sounds like your email redundancy is serial - that is, incoming mail has to go through SendGrid and then through your host's system,
It has to be incoming mail to Sendgrid then to your host email system anyway, then to ElkArte, otherwise, why would your host "turning off SMTP Restrictions" solve anything regarding received email?
{EDIT: And now you've discovered Sendgrid is munging up outbound email, because it's configured to "hide" your actual URL and server from your email recipients.. ☹]
Anyway, once the rest of your forum is operating the way you want, if not sooner, go back and look at this email thing and figure out why your host isn't capable of meeting your needs.. I'll bet you find the host actually is able to meet your needs (I would not be surprised if turning off the SMTP restrictions solved the "spam-folder" issue - that supposedly drove you to seek another solution - if it wasn't actually solved earlier), and SendGrid can be eliminated.
Title: Re: Setting up SMTP Mailing service
Post by: Steeley on July 16, 2024, 05:15:07 pm
Quote from: Steeley – I'm a big fan of "KISS" ... the fewer things that can go wrong, will usually result in fewer things going wrong.
Well thats an amazing elaboration Steeley! and you are right ! I am using SendGrid only because mass emailing through my host will get me blocked as they advised me, but since I wont be having like hundreds of emails being sent and the forums have only 1 member at the current moment which is me I cannot expect a lot of emails going through!
You offer a good point, but how would one go on with setting up the mail system so it doesn't go through PHP ? or does it need to go through PHP if I decide to use my hosting provider as the email server ?
I am providing a screenshot of my hosting mailbox information below, since these mailing systems confuse me a bit, should this be the information entered for SMTP ?
Title: Re: Setting up SMTP Mailing service
Post by: Steeley on July 17, 2024, 01:47:43 pm
Set up the email account(s) for your foum on your host like you would any other type of email account.
You will want at least an account for elkArte to use to send and receive emails (copies/notifications of forum posts, newsletters, whatever..), and one for webmaster communications. If you are going to allow Post By Email, that will be a different set of issues, let's crawl before trying to stand and run..
Now, go into ElkaArte Admin and configure communications to use each account.
That's all you have to do.
If it doesn't work right, or at all, then debug the EA configuration, and/or figure out what's going on with the host SMTP email handling.
It's been more than 5 years now since I set up email communications with ElkArte so I'm going to have to think/look back, but as I recall, this part was very simple. (What took some trickery was the fact that I have about 20 "boards" and PBE, and some fun cron jobs running to make that work). I think I had to work with spuds a bit to resolve some legacy issues in the php sendmail (EA v 1.16), but those have been corrected in later releases..
The only time I've ever had any issues with sending and receiving email with EA is when my host's email servers were "updated " and the new configurations broke the process, that my host had to go back in and fix.. So, make sure you have your own separate "user" (in addition to admin or "webmaster" account) and email addy for it, so you can "test" what your users will see, but more important, see when stuff just mysteriously stops working and know your host just did something to the email server!
Forget Sendgrid, don't worry about anything re: php unless your testing shows there's a problem there, and if you can't figure that out, come to us and we can focus on solving the problem rather than finding a suitable bandaid or work around that nobody has ever used before..
Your host's email doesn't know or care where on the server domain EA resides, and EA doesn't care where it is either - mydomain.com/forum, or forum.mydomain.com/forum, it doesn't matter when it comes to email handling. EA just needs to know the email account addy, and credentialing to get into it. The host's email has no idea where the account access attempt is coming from(*), just needs to know it had the right credentialing.
*exception: there's some handshaking and checks that now goes on between the SMTP email server and the accessing "client" (EA in this case) for security purposes, but that should be moot if EA is on the same box as the server - there should be no 'security 'handshaking" you have to worry about in that situation.
What I recommend is to close down this thread, and the Email template thread, then start over - reconfigure your installation for local host email, and create a new email thread if you run into problems, based on resolving the problem, not trying to configure the workaround attempt. Trust EA to work as intended "out of the box" and don't try to deal with theoretical problems unless you actually encounter them. If they do manifest, then fix it, rather than try to sidestep it.
Oh, and unless there's a very good reason to operate in a subdomain, don't complicate things unnecessarily.
[EDIT: I believe C-Panel softaculous has listserve support/ties at the server level, which may (or may not) be an easier/more elegant solution if your forum becomes so successful it outgrows your host's email volume tolerance. But worry about dealing with that problem only if you actually encounter it.