Phone Resets Due To Dns Or Other Connectivity Issues; Phone Does Not Power Up; Cisco Ip Phone Security Problems; Ctl File Problems - Cisco Unified IP Phone 8941 Administration Manual

• If the Restart Cause field displays Reset-Reset, the phone receives a Reset/Reset from Cisco Unified
• If the Restart Cause field displays Reset-Restart, the phone closed because it received a Reset/Restart

Phone Resets Due to DNS or Other Connectivity Issues

Problem
The phone reset continues and you suspect DNS or other connectivity issues.
Solution
If the phone continues to reset, eliminate DNS or other connectivity errors by following the procedure in
Determine DNS or Connectivity Issues, on page

Phone Does Not Power Up

Problem
The phone does not appear to be powered up.
Solution
In most cases, a phone restarts if it powers up by using external power but loses that connection and switches
to PoE. Similarly, a phone may restart if it powers up by using PoE and then connects to an external power
supply.

Cisco IP Phone Security Problems

The following sections provide troubleshooting information for the security features on the Cisco IP Phone.
For information about the solutions for any of these issues, and for additional troubleshooting information
about security, see Cisco Unified Communications Manager Security Guide.

CTL File Problems

The following sections describe troubleshooting problems with the CTL file.

Authentication Error, Phone Cannot Authenticate CTL File

Problem
A device authentication error occurs.
Cause
CTL file does not have a Cisco Unified Communications Manager certificate or has an incorrect certificate.
Communications Manager Administration.
from Cisco Unified Communications Manager Administration.
Cisco Unified IP Phone 8941 and 8945 Administration Guide for Cisco Unified Communications Manager 10.0 (SCCP

Cisco IP Phone Security Problems

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and SIP)
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