We have Exchange-based mail gate and Zimbra after that. Exchange receives mail from outer world and after AD checking relays all necessary mail to Zimbra.
email@example.com -- > firstname.lastname@example.org
All works fine, mail is delivered without errors.
The problem is:
When email@example.com send mail with specific attach (unzipped MSOffice document) he receive NDR from Exchange and firstname.lastname@example.org don't receive this letter in his inbox.
zmmsgtrace shows nothing about this letter. email@example.com Inbox is working fine with no problems. Mail without attaches delivers fine.
Can't find errors in Exchange log files.