Help with Google Voice

So, I have tried google and am not getting much help from there. My issue is the calls don’t seem to be working for me. I set up my voice account and linked it to my phone. I tried a test call to my daughter’s phone and I can hear it ring, but when she picks up I can’t hear her and she can’t hear me. Same if she calls. I can hear the call tone, but as soon as I pick up, nothing. Sound and mic work for everything else. I don’t know if there is something I am missing. I have gone through the GV settings multiple times. Messaging works fine, but that doesn’t help with calls.

Ok, well, I figured out it was my VPN, however I’m still not sure why it is doing this. I turn it off, voice works perfectly. I turn it on, no sound and it drops the call after 10 seconds every time.

Those symptoms are pretty indicative of an RTP issue, likely due to IP addresses being mangled by your VPN. There is likely no fix with Google Voice. (With traditional SIP, you would use a STUN server or SIP proxy.)

Basically, RTP data is bad at going over NATed (and thus many VPN) connections. Since RTP data is UDP and stateless, the stateful NAT routers are unable to keep track of the traffic as it goes through them, thus the traffic is simply dropped, and you end up without any audio. (Depending on exactly how things are configured, sometimes you will get uni-directional audio; often outbound but not inbound.)

I know this used old, but did you ever get this resolved?

Google Voice Community article

In case this old issue is still a problem…

It doesn’t make sense that UDP cannot traverse a vpn. Most likely the packets are sent with the nofrag option and are too big to fit through the vpn. Try reducing the MTU at your end so it will send smaller packets.