When error occurs, this error is delivered in appropriate event. For example, when connection error occurs, ConnectionStatusEvent is the event for this error. In case of error with SIP calls, CallStatusEvent contains status=FAILED and error description in 'info' field. If the error cannot be classified, it will be delivered to the client as Error Event with error description in 'info' field.
Also ErrorEvent will be delivered to the client in case of web server interaction errors when method 'event' is called.