Good morning,

I have a 3 server Exchange DAG (each with the UM role/service) and whenever I place one of the servers in maintenance mode, I get the following alert(s) from Lync/UM:

LS Exchange Unified Messaging Routing(44022 - LS Exchange Unified Messaging Routing): An attempt to route to an Exchange UM server failed. The attempt failed with response code 504: X.X.X.X.
Request Target: [YYY@X.X.X],
Call Id: [ba410a14f4dbd4e007fb08e6b7fcee26].
Failure occurrences: 2, since 6/23/2015 7:54:43 AM.Cause: An attempt to route to an Exchange UM server failed because the UM server was unable to process the request or did not respond within the allotted time.
Resolution:Check this server is correctly configured to point to the appropriate Exchange UM server. Also check whether the Exchange UM server is up and whether it in turn is also properly configured.

When this happens, voicemails destined for that user cannot be left.
Is there a way I can ensure the UM integration knows that an Exchange is offline, to prevent these routing issues? I would have expected the UM integration to 'know' when the Exchange topology changes.

Thanks in advance,

Greg

Hello,

I have no problem when I start maintenance mode on my servers.

I presume you run the StartDagServerMaintenance.ps1 script in $exscripts?

Also, are the UM services set the same on all your servers?

Karl

Hello,

Is there any update on this?

Have you also verified that all the servers have the certificate properly bound to the UM service?

1..3|%{Get-ExchangeCertificate -Server server$_ |where services -like *um*}

Verify the thumbprint is equal on all three.