I have a feeling that SASL auth isn't being setup correctly during installation. Even trusty old Roundcube can't send mail due to the auth error:
# tail -n 20 /var/log/mail.log
postfix/smtpd: connect from localhost[::1]
postfix/smtpd: warning: SASL authentication failure: cannot connect to saslauthd server: No such file or directory
postfix/smtpd: warning: localhost[::1]: SASL LOGIN authentication failed: generic failure
postfix/smtpd: disconnect from localhost[::1] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
Same issue if I try to setup Gmail 'send as' Account for any of the domain names hosted on the server. Using Port 587, TLS, correct email address, correct password. Authentication failed message presented.
So, at the moment, I can't use Gmail to "send as" (ie. authenticate via the server/domain) And, I can't use Roundcube (the usually trusty backup) But sending email via Usermin email interface works, as I expect that's just using port 25. Form submission using phpmailer works through port 25 Form submission using phpmailer with TLS/Port/Username/Password authentication fails (same as Gmail and Roundcube)
Seems to be an issue since the new installer as I've done hundreds of installs prior to this (though usually Ubuntu 14.04 and 16.04).
I'm not a SASL / Postfix pro (as Virtualmin's always handled that for me in the past). I've tried quite a few mods to /etc/postfix/main.cf and master.cf (and reset them back to original) many times.
To the Virtualmin Devs, let me know if you need to see any specific logs to help rectify this issue.
Yes, saslauthd is running:
service saslauthd status
● saslauthd.service - LSB: saslauthd startup script
Loaded: loaded (/etc/init.d/saslauthd; generated; vendor preset: enabled)
Active: active (running) since Mon 2017-08-21 02:32:22 UTC; 6h ago
Process: 338 ExecStart=/etc/init.d/saslauthd start (code=exited, status=0/SUCCESS)
Tasks: 5 (limit: 4915)
├─386 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 5
├─387 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 5
├─388 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 5
├─389 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 5
└─390 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 5
I just can't figure it out. Suggestions appreciated. Please.