I assume that a test email was received because gmgr says it was removed from the queue. In RoundCube, Inbox there is no message, so my assumption is that RoundCube either does not know where my inbox is or cannot read it if it does.
I can see the .../vhost... directory so the further assumption is that mail was delivered there.
Does this adequately describe "cannot find inbox"?
EDIT:
Following some postfix debugging advice, I tried /usr/sbin/sendmail -v gbrooks@... The system hangs, and mail log reads:
13:14:35 mail dovecot: imap-login: Login: user=<gbrooks@p...
13:14:35 mail dovecot: imap(gbrooks@p...): Disconnected
EDIT #2:
Postfix debugging revealed nothing of interest. Dovecot debug logging (auth_debug = yes, mail_debug = yes, auth_verbose = yes) did not add any data after postfix/gmgr removed the mail. I cannot find where it went, and the Inbox remains empty. I remain stumped.
EDIT #3:
$config['smtp_debug'] = true;
did not add any entries into either /var/log/mail.log or .../roundcubemail-1.2.2/logs when mail was received and moved by postfix/gmgr. This is getting nuts^2.
This missing mail behavior began after implementing a MySQL database for usernames and addresses. As should be obvious, I am at least able to authenticate. And send mail. Just can't receive any.