RTCPeerConnection: icecandidateerror event

The WebRTC API event icecandidateerror is sent to an RTCPeerConnection if an error occurs while performing ICE negotiations through a STUN or TURN server. The event object is of type RTCPeerConnectionIceErrorEvent, and contains information describing the error in some amount of detail.

Bubbles No
Cancelable No
Interface RTCPeerConnectionIceErrorEvent
Event handler property RTCPeerConnection.onicecandidateerror

Description

The error object's errorCode property is one of the numeric STUN error codes. There is one additional, WebRTC-specific, error which lies outside the valid STUN error code range: 701. Error 701 indicates that none of the ICE candidates were able to successfully make contact with the STUN or TURN server.

The 701 error is fired only once per server URL from the list of available STUN or TURN servers provided when creating the RTCPeerConnection. These errors occur only when the connection's ICE gathering state is gathering.

Example

The following example establishes a handler for icecandidateerrors that occur on the RTCPeerConnection pc. This handler looks specifically for 701 errors that indicate that candidates couldn't reach the STUN or TURN server.

When this happens, the server URL and the error message are passed to a function called reportConnectFail() to log or output the connection failure.

pc.addEventListener("icecandidateerror", (event) => {
  if (event.errorCode === 701) {
    reportConnectFail(event.url, event.errorText);
  }
});

Note that if multiple STUN and/or TURN servers are provided when creating the connection, this error may happen more than once, if more than one of those servers fails. Each provided server is tried until a connection is established.

Specifications

Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'icecandidateerror' in that specification.
Candidate Recommendation Initial definition.