/mcpfirmware load ID exists on the TFTP server (on the Cisco Unified OS Administration page, access Software Upgrades > TFTP File Management, then look for the file name as specified by load ID). 19 DigestAuthChallenge - (SIP only) A SIP device configured for digest authentication attempted to register with invalid credentials. Unified CM has responded with a challenge (401) to request new credentials. 20 DigestAuthChallengeForID - (SIP only) A SIP device attempted to register without a device name or MAC address. Unified CM responded with a challenge (401) which requests the device to resend the REGISTER message and include an Authorization header containing a user ID. Unified CM will use this user ID to attempt to find the device in the configuration database. 21 DigestChallengeTimeout - (SIP only) A SIP device requiring digest authentication sent a REGISTER message and Unified CM responded with a challenge (401) to request the authorization credentials. The device did not resend the REGISTER within the 30-second timeout interval. 22 ExpiresTimeTooSmall - (SIP only) A SIP device attempted to register with an Expires value smaller than the configured SIP Station Keepalive Interval value in the Call Manager Service Parameters. Unified CM responded with 423 Interval Too Brief and the device 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 178/343