Additional info by switching the home= and uid= settings in the config.
userdb { args = home=/nfs/maildir/vmail/%u uid=vmail gid=vmail mail_location=maildir:~/Maildir driver = static }
We got the effective id, but then home was unset and the user became the home setting. lol
Dec 14 15:56:20 test2 dovecot: auth: Debug: master userdb out: USER#0112586836993#011home=/nfs/maildir/vmail/home#011uid=503#011gid=503#011mail_location=maildir:~/Maildir Dec 14 15:56:20 test2 dovecot: pop3-login: Login: user=<home>, method=PLAIN, rip=::1, lip=::1, mpid=24686, secured, session=<jN2ZEtLQegAAAAAAAAAAAAAAAAAAAAAB> Dec 14 15:56:20 test2 dovecot: pop3: Debug: Added userdb setting: mail_location=maildir:~/Maildir Dec 14 15:56:20 test2 dovecot: pop3(home=/nfs/maildir/vmail/home): Debug: Effective uid=503, gid=503, home= Dec 14 15:56:20 test2 dovecot: pop3(home=/nfs/maildir/vmail/home): Debug: Namespace inbox: type=private, prefix=, sep=., inbox=yes, hidden=no, list=yes, subscriptions=yes location=maildir:~/Maildir Dec 14 15:56:20 test2 dovecot: pop3(home=/nfs/maildir/vmail/home): Error: user home=/nfs/maildir/vmail/home: Initialization failed: Namespace '': Home directory not set for user. Can't expand ~/ for mail root dir in: ~/Maildir Dec 14 15:56:20 test2 dovecot: pop3(home=/nfs/maildir/vmail/home): Error: Invalid user settings. Refer to server log for more information.
Jack