I have been getting reports of random NDR's with error code Remote Server returned '554 5.6.0 Corrupt message content; STOREDRV.Deliver.Exception:ConversionFailedException.ConversionFailedException.TextConvertersException; Failed to process message due to a permanent exception with message The message content has become corrupted. ConversionFailedException: Content conversion: Body conversion failed. [Stage: PromoteCreateReplay]'.
The last one reported was a user that was accepting an internal meeting invite. I did some powershell searching to see how often this has happened over the last 3 months. It has happened about 25 times during that time period. I checked with a couple of users and found the emails in question had attachments. The both had a word file attached.
This seems to be sporadic. How would I go about identifying if the issue is caused by Outlook or if it is caused by Exchange? I have seen a couple posts about disabling antivirus but I want to first know on what side the issue is occurring.
Once the user gets the NDR the email is corrupt. From that point nothing can be done with the email except delete it.
If anyone has any ideas how to identify what is causing this please let me know.