Error type: "Forbidden". Error message: "The referrer https://www.googleapis.com/youtube/v3/search?part=snippet&channelId=&maxResults=4&order=date&type=video&key=AIzaSyCvd0_pEmMhZWWo2NhY1PKQAzSGG7ej-jQ does not match the referrer restrictions configured on your API key. Please use the API Console to update your key restrictions." Domain: "usageLimits". Reason: "ipRefererBlocked".
Did you added your own Google API key? Look at the help.