I am facing a weird issue with a user on his 7965. When he tries to press the MESSAGE key, he receives a following error.
Error: 874001 Server failed on command. Voice mail server is unavailable. Try again later.
His phone freezes and unable to come out and has to unplug the phone to come out.
I am running with the CUCM 18.104.22.168900-2
Unity Connections: 7.1.5ES33.32900-33
I believe this is related to Visual Voice Mail.
Have you configured it according to follloing link.
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