I have 2 polycom ip 550's running on my 3cx phone system. As of yesterday one has quit working. Under extension status it shows that it is not registered. When I go under phones it does not show up at all. I have attempted to delete and rebuild the extension and even logged into the phones web interface to make sure settings were correct. The even log shows the same line over and over. 15:53:27.826 [CM102001]: Authentication failed for SipReq: REGISTER 10.1.10.108:5060 tid=22c7a59572858516 cseq=REGISTER email@example.com / 2 from(wire); Reason: Credentials don't match, check that authorization-ID and password match the ones in extension settings I have verified time and again that they match and still no luck. Any suggestions? or more information that I could provide?