Having this error message on one of our IP phones (Avanti 3015ip)

Verified our other IP phones are working and connecting fine. This phone has been sitting for a couple of years and now this error, phone was a working unit unplugged working.

Any help would be appreciated!

Has anything changed to the network while this phone was unplugged? Did you check the settings on the phone itself?

Bad firmware load is usually the cause, if this happens late in the boot process. Also check the RTP settings are all deleted.