Did we ever confirm where the "stuck" email message comes from? Here is an example of local submission:
Mar 5 01:05:04 spike postfix/pickup[95787]: 3kyM4J5pqmzJrQ2: uid=1001 from=<wietse> Mar 5 01:05:04 spike postfix/cleanup[95928]: 3kyM4J5pqmzJrQ2: message-id=<3kym4j5pqmzj...@spike.porcupine.org> Here is an example of mail from the network: Mar 5 00:00:12 spike postfix/smtpd[95578]: 3kyKdS499kzJrQ1: client=host.example.com[10.215.220.112] Mar 5 00:00:12 spike postfix/cleanup[95589]: 3kyKdS499kzJrQ1: message-id=<CANc4c+T1ctsNwcJMCbWYg8+L5FLrm0r2gw0Qf3NM=yk4ovv...@mail.gmail.com> Which of these applies to your case? Wietse