Issue Description :
The phone is not working and shows no service. The extension is not working either.
Possible causes :
- The firewall of the router (if its a third party router) may filter the SIP lines.
- The device (Handset) may not be working.
- The Ethernet cable has been replace
- Try different port and switch and reboot the device
- Try other device to test the extensions
- By pass the third party router, connect the the router that we issued directly to internet and connect the device