WebRTC - ICE state: cancelled / ICE failed, your TURN server appears to be broken?

Question

JavaScript

Hello, I am making a chat on WebRTC, rented my Stun/Turn, set it up, here it returns srflx and relay.
At connection some time works, then throws out the specified error. What is Firefox, what is Chrome.
In about the following:

All the necessary ports on the server, it seems, have opened.
I'm new to this, so don't blame me.
Thank you.