One-way audio on 3CX
Fix calls where one side can't hear.
| What you need | Affects |
|---|---|
| Admin access to the 3CX Admin Console, and access to your router or firewall | Calls with missing audio |
1. Fix the network
- Turn off SIP ALGTurn off SIP ALG on your router. It often breaks call audio.
- Open the portsForward the ports 3CX needs to it, using the firewall checker as a guide.
- Check the public IPMake sure the public IP set in 3CX is correct.
2. Test
- Test on mobile dataCall from the 3CX app on mobile data to rule out the office network.
- Test both waysMake an inbound and an outbound call.
Troubleshooting
| Problem | Likely cause and fix |
|---|---|
| Audio drops after 30 seconds | Usually the same NAT problem. Check SIP ALG and the public IP. |
| Only remote phones are affected | Check the ports for remote extensions are open. |