Some thoughts.
1) Have to create an account & login? Why? Should be able to do this a bit more anonymously.

2) You need to have a 'test call' option. Browser / firewall / whatever compatibility is a thing and there are known issues with webrtc with certain security appliances.

https://www.reddit.com/r/sonicwall/comments/94efxq/sonicwall_possibly_blocking_webrtc_traffic/
https://campus.barracuda.com/product/webapplicationfirewall/doc/49054741/how-to-enable-websocket/
and so on....

-Dave