Error when embedding youtube channel

Hi,

I always get this error when I try to embed my youtube channel: Sorry, that does not seem to be a link to an existing video. Please confirm that the link works in your browser, and that?the owner of the video allowed embed sharing permissions (otherwise, contact the owner of the video to allow embedding). Then copy that full link in your address bar to paste here. If you are sure your link is correct, then (1) your API key may be too restrictive (check here) or (2) you have reached your Google quota (check here). You can apply to Google for a?quota increase here.

The link is correct, the API has no restrictions at all and I did not reach my google quota.

Any ideas?