Hi @Frans Beers ,
Does this issue happen to all the users in your organization? Or only parts of them?
I noticed that you mentioned this issue only occurs occasionally but not always. Does the issue occur only under certain circumstances, such as specific recipients or specific image format? Or happen to all RTF format email messages?
When the Outlook client gets outside the office and connect to Exchange Online, they have no problem. When they return inside the office the problem stays away and never returns.
During this priod, are you using the same Outlook desktop client? From the perspective of the Outlook client, to confirm if the issue is related to the Outlook client, please try to always using the same Outlook desktop client and see if the issue has any difference.
'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]
I did some search about this error message and found that Exchange server version and Outlook versions may cause issues like this, please make sure you have upgraded your Exchange server and Outlook version to the latest and see how everything goes.
Any update, please feel free to post back.
Update:
Hi FransBeers-1153,
Thanks for your reply. Apologize for the delay. I really did lots of search about your issue and also tried discussing this issue with Exchange team. However, both of us could not found any settings or parameters related to your issue.
Is this a problem that has only recently occurred in the specific Exchange version? According to my search, similar issues happened in the old versions of Exchange. So, to exclude the factor of Exchange version, please try to upgrade your Exchange version to the latest and see if the issue has any difference.
Besides, the RTF format itself is a relatively complex format in the transmission process, compared with HTML and Plain Text. I also encountered some other issues related to specific RTF format when sending emails. As a temporary workaround, before we found more possible solutions, it is suggested to use HTML format or add images as attachment when sending email messages. Thanks for understanding.
If an Answer is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.