Error: #550 4.4.7 QUEUE.Expired; message expired ##

I am having an issue with one of my client’s exchange servers. They have one external client that they cannot send any email to but if I get the external client to send a test message, it will be received without any issues. I have confirmed that he is using the same email address as we have. The domain is @iastate.edu

When I send a test message to the external clients email address, it shows up in the outbound exchange queue and never leaves. Eventually, I get the following error;
Error: #550 4.4.7 QUEUE.Expired; message expired ##
If I open the receive log files, I can see that there are no messages showing an attempt to deliver that message.
The folder I was looking in was as follows;
C:\Program Files\Microsoft\Exchange Server\V14\TransportRoles\Logs\ProtocolLog\SmtpSend

Exchange mail flow troubleshooter doesn’t show anything wrong

What can I do to narrow down where the problem may be?
johnny181Asked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Andy MInternal Systems ManagerCommented:
To start with I'd check dns. Make sure your email server can resolve the mx record for the client's email server correctly and that your email server can actually contact it.

Queue expiry typically indicates that the sender's server could not contact the recipient server or the recipient server is simply not accepting the connection.

If you can resolve/connect to it try running a telnet from your server to theirs and send an email via that - this gives you an idea of what is happening along each step of the progress. If that works fine it may be something to do with your send connector - set up a separate one as a test and see what happens.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
johnny181Author Commented:
Ah, that is the funny thing. I went to MX Toolbox and their mail server shows mailin.iastate.edu. When I ping that from the server, I get a response of 129.186.140.10.
0
Andy MInternal Systems ManagerCommented:
That appears to be correct - that hostname resolves to that IP on my system as well. If you are getting a ping response on your mail server for that then the connection/dns seems fine. I would try sending an email via telnet through that - may give you an idea of what part the process fails.
0
johnny181Author Commented:
Over the weekend, I went through the DNS on the Windows 2008 server and all appears to be good.
I sent another test a few minutes ago and one thing that I see now in the SMTP log files is the following;
451 4.7.1 Please try again later (TEMPFAIL)
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Exchange

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.