I have an issue similar to the link below. About 2 weeks ago we had one phone not able to place calls. It could receive calls but could not dial out. Reseting the phone did not fix the problem. I configured a 2nd phone with a button using the same DN and it couldn't place outbound calls either. It seemed like the problem was with the DN not the phone. In any case I rebooted the UC520 and the problem went away. About a week later a 2nd, different phone was affected by the same problem and I had to reboot again. In my case neither the config or IOS and CME versions have changed in almost 2 years. I don't understand why this would start happening with no changes to the system. I am running IOS 15.1(2)T2 and CME 8.1.
Any ideas how to troubleshoot this? What would be good debug commands to use and/or gather more info?
Thanks,
Diego
https://supportforums.cisco.com/message/3721512#3721512
