I recently purchased two 7961 phones for use in a new office we recently added to our company. One of them keeps trying to register after being configured and upgrading. It will occassionally complete registration for 30 seconds to a minute, then return to the registration rejection loop.
We're running call manager 188.8.131.520-13.
Please reply if you have any ideas, or need more info from me. I'm relatively new to this system, so no flames please