Ever found out why some messages are stuck in your Exchange Que? With one of these errors:
451 4.4.0 DNS Query Failed
400 4.4.7 Message Delayed
Just read on and i will explain how to solve it.
Open your Exchange Management Console
Go to: Server Configuration > Hub Transport > Properties. The screen below will pop-up.
Then go to the tab: Internal DNS. If you have one or more Network adapters, like i have. Select the right adapter. If you've selected the right one, the DNS field will be filled in for you.
Also take a look at the External DNS Lookups tab. And select the same adapter here like you did earlier.
With these settings the errors in the Que will be gone.
