#550 4.4.7 QUEUE.Expired; message expired ## With LastError "A storage transient failure has occurred during content conversion." In submission Queue. (Exchange 2013)

Question

Greetings,
We seem to be having a problem with some users who are attempting to send e-mails from within the organisation to an external domain. Not all users are affected, and not all outgoing e-mails have this issue.
Some e-mails get stuck in the submission queue. This is the error message in Last Error : "A storage transient failure has occurred during content conversion."
Days later, the internal user who send the message gets a #550 4.4.7 QUEUE.Expired; message expired ## NDR.
We did have some initial configuration issues, but these were fixed more than a week ago :
- The external FQDN during EHLO was set to the wrong address, now pointing to the correct one.
- SPF record was updated with new IP adress.
Here is some additional information on the issue :
- Not on any blacklists - checked using dnsbl.info
- Telnet to remote servers works from exchange server, connections are accepted and can send mail.
- Outbound SMTP test ran using Microsoft Remote Connectivity Analyser : Passed with both External (Static) and Smarthost IP.
- This seems to happen only with emails that have an attachment and that are transfered, but only for the affected users. 
- If content from these e-mails is manually copied over to a new email, email is sent to destination without problem.
Configuration information :
- Exchange 2013 running on Windows 2012 Datacenter with all latest updates.
- Outgoing e-mail is sent via smarthost. Only one outbound transport rule is active.
- Using internal DNS server.
- There is only one mailbox database.
Thank you for taking the time to read this!

Answer 1

On Wed, 16 Jan 2013 15:31:14 +0000, Ipigi wrote:
>Sorry, I often get some terms mixed up when I explain things as our users use the French version of outlook.
>
>E-mails are not transferred, but forwarded manually from their outlook. Message format in outlook is set to HTML and not Rich Text when they foward the e-mail.
Do they forward the message as an attachment?
>When forwarded internally, this is in the internet headers :
>
>Content-Type: application/ms-tnef; name="winmail.dat" Content-Transfer-Encoding: binary
Within your organization I'm prety sure that messages will use TNEF.
What does the message contain at the external recipient's side?
>It really seems to me that Exchange is not converting RTF to Plain Text. The first link you provided states in it's final paragraph that Exchange should be doing this conversion.
If you can, try creating a mail-enabed Contact for one of the external
recipients and set the message format on that.
>If I disabled TNEF as that link suggests, offending messages will get stuck in the submission queue again.
>
>I thank you for your help so far. This is not an issue I've had with any previous installations/migrations of Exchange that I have done.
>
>Please let me know if you need any additional information.
Have you tried UNsetting TNEF on the remote domain?
Set-RemoteDomain Default -TNEFEnabled $null
That should leave it up to the client to determine the format. It's
probably not what you're after, but see it makes a difference in the
format.
Rich Matheisen
MCSE+I, Exchange MVP
--- Rich Matheisen MCSE+I, Exchange MVP