I have a friend who is behind a strict corporate firewall who can use https://meet.jit.si/ just fine using the TURN server you have.
However when I set up my TURN server he cannot get even a relay candidate from it using this sample site:
I use turns: prefix and port 443, transport=tcp just like you.
He can access the TURN server https site from browser though. So the dns and cert should be fine, at least using https. (it shows the same thing to create admin user, etc. as your turn server)
So I think his firewall somehow blocks it when using webrtc but I am clueless as I am not really familiar how corporate firewalls block traffic, I mean based on what.
(My TURN server works fine for me and for a lot of others who is not behind a strict firewall.)
Do you have an idea guys what should I do differently or could you show me your config?
Thanks in advance,