Issue receiveing emails from certain mail servers. eg Office365 &

I am having issues with emails sent to one of my customers (SBS2003 / Exchange 2003 (Version: 6.5.7638.1).

I have asked for any NDR's to be sent to me and this is what they are saying:
9/6/2015 12:32:24 PM - Remote Server at (XXXX) returned '550 4.4.7 QUEUE.Expired; message expired'
9/6/2015 12:12:19 PM - Remote Server at (XXXX) returned '451 4.4.0 SMTPSEND.SuspiciousRemoteServerError; remote server disconnected abruptly; retry will be delayed'

Original message headers:
Received: from ( by ( with Microsoft SMTP
 Server (TLS) id; Fri, 4 Sep 2015 12:29:47 +0000
Received: from ([]) by ([]) with mapi id
 15.01.0262.011; Fri, 4 Sep 2015 12:29:47 +0000

I applied Hotfix 948963 ( last night but this stopped emails being received from my Exchange 2007 Server. I have since removed this and emails are being delivered again.

Any help would be appreciated.

Many thanks.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

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.

I'm suspecting you're using a third party filter/firewall software/hardware solution? In that case, you have to check the rules if there's anything you can whitelist MS servers.
KubicAuthor Commented:
Thank you for your comment. I have no third party filters running. The firewalls don't seem to be an issue either.
Does that mean whitelisting all MS 3rd party Servers manually? Is there a list of the ones used?
Thanks again.
Probably whitelisting it manually is the fastest solution right now. There's no real list, only subdomains as listed in their SPF record:

        "v=spf1 ip4:157.55.9
.128/25 include:_sp ~all"

Each entry has it's own entry again, for example, the first hostname gives you:
        "v=spf1 ip4: ip4: ip4: ip4: ip4: ip4: ip4: ip4: ip4: ip4: ip4: ip4:65.
55.94.0/25 -all"

So you need to add quite a few things.

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
KubicAuthor Commented:
Thank you.
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
Email Servers

From novice to tech pro — start learning today.