Changing the redirect uri to
http://www.awaycamping.com/sources/ext/endpoint?hauth.done=Google
got past the uri error to the permissions page. Click Allow, now a 500 error.
2017/03/29 19:33:03 [error] 4323#0: *4933836 FastCGI sent in stderr: "PHP message: PHP Fatal error: Call to undefined function fatal_error() in /var/www/clients/.../web2/web/sources/controllers/Extauth.controller.php on line 243" while reading response header from upstream, client: 137.118....., server: awaycamping.com, request: "GET /index.php?action=extauth;provider=google;sa=auth;member=1;s2d9a0TC4vW=1071ps2d9a........KGh3oVMX HTTP/1.1", upstream: "fastcgi://127.0.0.1:9011", host: "www.awaycamping.com"