/mcp4 DeviceNameUnresolveable - For SIP third-party devices this means that Unified CM could not determine the name of the device from the Authorization header in the REGISTER message. The device did not provide an Authorization header after Unified CM challenged with a 401 Unauthorized message. Verify that the device is configured with digest credentials and is able to respond to 401 challenges with an Authorization header. If this is a Cisco IP phone, the configuration may be out-of- sync. First go to the Cisco Unified Reporting web page, generate a Unified CM Database Status report, and verify that "all servers have a good replication status." If DB replication looks good, reset the phone. If resetting the phone doesn't fix the issue, restart TFTP and Cisco CallManager services. For all other devices, this reason code means that DNS lookup failed. Verify that the DNS server configured via the OS Administration CLI is correct and that the DNS name used by the device is configured in the DNS server. 6 ConnectivityError - The network connection between the device and Unified CM dropped before the device was fully registered. Possible causes include device power outage, network power outage, network configuration error, network delay, packet drops, and packet corruption. It is also possible to get this error if the Unified CM node is 5/24/26, 3:34 AM System Error Messages for Cisco Unified Communications Manager 15 - Cisco https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/err_msgs/15_x/ccmalarms15.html 174/343