YT Thumbnails not appearing or playing?

hi there

I have been using your awesome plugin with great effect until a couple of weeks ago when I tried to add another few videos.

Going through the usual process everything appeared ok and then when I look at the page (https://bestlifeintheworld.com/videos/) there are grey icons in place of what should be thumbnails.

Any ideas as to why this is not working anymore?

Thank you in advance!

Ben

https://www.ads-software.com/plugins/video-list-manager/