The referrer https://www.googleapis.com/youtube/v3/channels/?id=UCXIb8l0FQAgPKOzUDoxzutA&part=statistics&fields=items%2Fstatistics%2FsubscriberCount&key=AIzaSyDwAwpB3ESvJbPLjhz9HpI4cH2OE8zAaNA does not match the referrer restrictions configured on your API key. Please use the API Console to update your key restrictions.