I went to my ISPCFG3 panel => System => Main Config => MAIL and checked "Use SMTP to send system mails" as well as configured the settings to use Google Apps, with my ap password. See settings: http://take.ms/Ulp7J and yet when ISPCFG3 sends me emails they all get refused according to my _dmarc policy as they do not come via SMTP. This was the case with an email from ISPCFG3 about not being able to add letsencrypt to one site. Code: Unauthenticated email from domain.tld is not accepted due to domain's 550-5.7.1 DMARC policy.
Works fine here on my servers. try to use non tls as recent php versions refuse to do socket connections when an ssl cert can not be validated by php or when the ssl cert does not match.
Thanks, apparently port 465 with SSL would be the alternative, I'll give it a try. Seen here: https://support.google.com/a/answer/176600?hl=en
