CUCM 10.5: L2 Updates May Get Stuck When Optional Email Notification Is Selected

So I encountered another issue today: I was updating an existing 10.5 CUCM cluster with a new patch ( and the process would get stuck after a few minutes of the upgrade initiation. The last line that I would see in the console and the installation log file is:|Upgrade (L2) Starting|

CUCM L2 Update stuck

What should follow next? Correct: an [optional] email from “” with a subject line “Upgrade (L2) CallManager Started — <node name>” should follow. It never did. Turns out, our SMTP Relay was not permitting relay from the CallManager’s IP address, so the installation could not proceed. Workaround: either opt-out of the notification email or fix your SMTP relay!

Hope this helps someone.

Leave a Reply

Your email address will not be published. Required fields are marked *