I have a Linux server that has stopped sending mail since I swapped in a new proxy server on my network.
The new proxy is working perfectly in all other respects, and is more or less a copy of the old one on new hardware, but as soon as I bring it online, mail in the Linux box starts deferring. The Linux box is set to access the net directly so I'm unsure as to why the proxy is causing this problem - all the deferred mail is internal to my network anyway!
When I run mailq, each message is listed with the following:
(host map: lookup (mydomain.co.uk): deferred)
or
(host map: lookup (uk.myActiveDirectory): deferred)
depending on how it was addressed.
Everything suggests DNS but as a bit of newb, I'm not sure where to go from here - any help appreciated!
thanks

what does below provide ?

Hi SAbhi, thanks for getting back to me. In the end, a reboot of the server sorted it out and all is working OK.