[Dovecot] TTY=unknown

I'm wondering if TTY=unknown should be consider as a warning or error. I'm busy perfectioning the organisation's mail server. I want it to run without any warning or error message.

==> /var/log/auth.log <== Aug 12 11:37:15 h1690641 sudo: mail : TTY=unknown ; PWD=/var/spool/postfix ; USER=root ; COMMAND=/usr/lib/dovecot/deliver -f sender@domain.com -d receiver

Thanks in advance,

Frank