c8fa26c0_Internal_Error_Codes___DocWiki__Descriptor
[Code] 31 [Explanation] A matched dial peer could not be used to place the call because the configured permission on it contradicted its use as an outbound dial peer. [Category] 181 [Descriptor] 
Outbound dial peer blocked
Cisco IOS Voice Troubleshooting and Monitoring -- Cisco VoIP Internal Error Codes - DocWiki
Descriptor