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.
firstname.lastname@example.org -- > email@example.com
All works fine, mail is delivered without errors.
The problem is:
When firstname.lastname@example.org send mail with specific attach (unzipped MSOffice document) he receive NDR from Exchange and email@example.com don't receive this letter in his inbox.
zmmsgtrace shows nothing about this letter. firstname.lastname@example.org Inbox is working fine with no problems. Mail without attaches delivers fine.
Can't find errors in Exchange log files.