Element Call ICE fails

When connecting to Matrix RTC/Element Call in Element Web the WebRTC connection may fail with this error: ¹

WebRTC: ICE failed, your TURN server appears to be broken, see about:webrtc for more details

This error may happen because you are using a web browser plugin which blocks WebRTC connections from working. For example, ProtonVPN has a setting called "WebRTC Leak Protection". Disabling this setting will allow the WebRTC connection to succeed. ²