During a recent Skype for Business-Exchange 2013 deployment, I tried running all calls to a DID, then to an Exchange 2013 UM Auto Attendant. After some hiccups I had it working, but painfully, dialing by extension and transfers did not work from the Auto Attendant. After doing some investigating, the Skype server wasn’t giving me an errors, and my syslog from the Audiocodes gateway was indicating calls were transferring.
However, the Exchange server gave me two errors regarding unified messaging: 1079 and 1136.
I tried lots of solutions, tested my environment numerous times, but nothing was working. If you look these errors up when doing a Skype for Business server deployment, you’ll often see Microsoft KB 3069206 come titled, “Exchange UM Auto Attendant cannot transfer calls to a phone or extension number in Skype for Business Server 2015“. Looks great and promising…
…but I’ve already updated the server to the latest CU.
With more Google-fu, I found my solution: I needed to change my certificate for the Exchange server.
According to this TechNet thread, the certificate assigned to the UM services on the Exchange server needs to have it’s subject name be the same as the Exchange UM server’s name. I had used the same UCC-SAN cert for UM services that I set up for the Skype for Business Edge server, and added all the subject alternative names needed.
The fix: perform a new certificate request from the internal CA, apply the certificate to the UM services, then restart the UM services on the Exchange server..
After that, call transfers worked!
Hope this helps someone.