TURN server connection fails between US-India and US-Poland

Question

Problem:
We are using Azure Communication Service video calling service and can successfully connect between computers in the US without any problems. However, when testing with our team in India and Poland, we were unable receive each other's audio/video.

Debugging:
We have tested other WebRTC solutions and know that at least one of our US members connects to a router using a symmetric NAT layer, but they are still able to connect with us in the US. This tells me ACS's TURN server is working in the US.
Using ExpressVPN (doesn't leak ICE candidates), I am able to connect to India and get audio/video from another device in the US. Presumably, ExpressVPN presumably is connecting to a datacenter somewhere that may have access to more network connections than a personal computer in someone's home, however.
The ACS javascript package gets information from the peers, so there is some successful connection, but I'm not sure if this is just successful REST based signaling without a successful WebRTC connection.

Question:
Are there options to add additional TURN servers?
Has the TURN server been tested to make sure it works from endpoints around the world outside of datacenters?
Any other possible reasons this problem could appear? - video encoding/decoding or something (I assume this isn't a problem because of WebRTC)?

Thanks for the help

Answer 1

Hi @Tommy L Sharkey ,

Thanks for your patience. We currently don't have options for users to define their own TURN servers but we want to learn more about your scenario. Can we get some calls from successful and failed scenarios to investigate the failures further?

And yes, TURN server been tested from endpoints around the world, when that happens usually hints to a specific network configuration on the user's environment.

Best,
Grace