Today one of my user report problem that one of mail has not been delivered in his mail box,

I have checked the logs main logs(var/log/maillog), mail has been delivered in logs

Feb 26 03:10:10 zimbra postfix/lmtp[22938]: 9A78F13A0031: to=<test@iabc.com>, relay=zimbra.iabc.com[]:7025, delay=4.4, delays=2/2.3/0.01/0.06, dsn=2.1.5, status=sent (250 2.1.5 OK)Feb

But when i run message trace command(with massage) it return 0 messages

Tracing messages
ID 9A78F13A0031
0 messages found

The same messages has been delivered out side of the domain.
Is there any other logs that can could help. do you think long massage subject(and id) was issue.