Got a call from a customer informing me that inbound mails are bouncing with 550 Unable to relay – but only on 1 of their Exchange 2010 Edge servers. The other server works fine.

First thing I ask is whether the receive connector on the Edge server has Anonymous permissions allowed – upon which they say Yes…..sigh!

Anyways, I decide to have a look and everything looks good on the receive connectors. I decide to renew the Edge subscription; test the Edge subscription between the Edge server and the AD site and all tests are successful. Yet mails are still “Unable to relay” inbound….sigh again!

I test with FullCompareMode parameter and notice that the AcceptedDomainStatus shows NotSynchronized. Check the Accepted Domains on internal server all looks good, but nothing gets synchronized to that one Edge server.

I create a test accepted domain, forced synchronization and notice the domain is being synchronized…..hmmm what now….I can’t just delete and recreate the authoritative domain!

I decide to rename the display name of the accepted domains and forced synchronization. This populated the Accepted domains on the affected Edge server.

Renamed the display name back and confirmed the name changes on the Edge server.

Tested inbound mail….working…sorted….YAY!!

I’m not sure why this occurred, but I’m sure someone else out there will experience the same issue.

Happy Edge’ing.

Michael