Turn off SIP ALG on your router
Fix one-way audio and dropped calls caused by the router.
SIP ALG is a router feature that often breaks VoIP.
Steps
- Log in to your router's web page (the address is usually on a sticker on the router).
- Look for SIP ALG, often under Advanced, NAT, Firewall or Security.
- Turn it off and save.
- Restart your phones and test calls in both directions.
Tip: Some routers supplied by internet providers hide this setting. Ask your internet provider if you can't find it.