Common Issues and Fixes

Issue	Resolution
Extension won't register	Check port (5060 vs 5160 vs 5300), credentials, NAT settings
No audio	Open RTP ports, set correct external IP
Incoming calls fail	Match Inbound Route with DID
Outbound calls fail	Verify dial pattern and trunk
Phone unregisters randomly	Adjust SIP keep-alive, check router/firewall
One-way audio	Validate NAT config, RTP forwarding

Some of these issues can be a hiccup in the network and disabling the trunks (all of them used for calling) for about 30 seconds and then restoring them will fix the issue.