Youtube API guide seems outdated compared to Youtube UI

I can’t seem to get any Youtube API key to work, always getting the same error:

{ “error”: { “errors”: [ { “domain”: “usageLimits”, “reason”: “ipRefererBlocked”, “message”: “The referrer https://www.googleapis.com/youtube/v3/videos?part=id&key=AIzaSyDZbPNPP-xgvaGK5U7e4Epc04Lntbw3GA4&chart=mostPopular does not match the referrer restrictions configured on your API key. Please use the API Console to update your key restrictions.”, “extendedHelp”: “https://console.developers.google.com/apis/credentials?project=33308775902” } ], “code”: 403, “message”: “The referrer https://www.googleapis.com/youtube/v3/videos?part=id&key=AIzaSyDZbPNPP-xgvaGK5U7e4Epc04Lntbw3GA4&chart=mostPopular does not match the referrer restrictions configured on your API key. Please use the API Console to update your key restrictions.” } }

Even with NO restrictions to the API …

What am I doing wrong ?

The page I need help with: [log in to see the link]