I was wondering why my question about getting a 410 error "Could not connect to Youtube 410 No longer available" has just disappeared.

Hello,
Youtube changed their API and now it requires an API key. The extension must be updated in order to work. You will be notified, as soon as there is an update available.

Thank you.
At least I know what is happening now.

I only see endless circles when I try to launch it in DW CC - and nothing has changed yet. What is the right procedure? As far as I know, this extension is still sold and seemed to having stopped working. Did I miss the update?

Hello Greta,
DMXzone Youtubizer needs an update, because of the changes in youtube API. This extension is currently not in our top-priority updates list so i don't know where exactly it will be updated.
Also it is not sold, but a free extension.

Teodor, thank you for your reply,
I see, it just popped up within DMXzone's video player (which is not a free extension). But as it seems it is not necessary anymore to use any DMXzone extension to integrate YouTube videos into websites now.