My phone rings but there’s no audio during calls.

This issue could be related to firewall settings, audio codec mismatches, or hardware faults.

1. Check Audio Settings:
   • Ensure the phone’s volume is turned up.
   • Try switching between handset, headset, and speakerphone to see if one works.
2. Codec Configuration:
   • Log into the Yealink web interface and check Settings > Audio Codec.
   • Ensure commonly used codecs like G.711, G.729, and Opus are enabled.
3. Firewall/Router Issues:
   • Some routers block VoIP audio while allowing SIP registration.
   • Ensure SIP ALG (Application Layer Gateway) is disabled in your router settings.
4. Test Another Network:
   • If using WiFi, switch to an Ethernet cable connection.
   • Try connecting the phone to another network to see if the issue persists.