The errorText property of the RTCPeerConnectionIceErrorEvent interface represents the STUN error reason text returned by the STUN or TURN server if there was an error during ICE negotiation.
If communication with the STUN or TURN server couldn't be established at all, this will be a browser-specific string explaining the error.
A string returned by the STUN or TURN server, or a browser-specific string explaining why communication with the server could not be established.
This example creates a handler for icecandidateerror events, which creates human-readable messages describing the local network interface for the connection and the ICE server used to attempt the connection. It then calls a function to display those messages and the value of the event's errorText property.
pc.addEventListener("icecandidateerror", (event) => {
const networkInfo = `[Local interface: ${event.address}:${event.port}]`;
const iceServerInfo = `[ICE server: ${event.url}]`;
showMessage(event.errorText, iceServerInfo, networkInfo);
});