Hi

I am guessing that you are using uBlock. If so, you just need to update the add-on - not an issue with Firefox, the add-on developers have updated their filters.

what kind of nonsense is that, ublock has been running for me for ages and youtube worked there too, what the heck is that? ublock cannot be updated

The developers of uBlock have updated the filters that uBlock uses. You will need to update the add-on, this support article will help:

https://support.mozilla.org/en-US/kb/how-update-add-ons

Look an Screen ;) NO Updates found

Please can you try uninstalling uBlock, closing Firefox, opening Firefox and reinstalling uBlock.

Why should I do that ? If the developer is not able to program his tool sensibly so that it updates itself correctly, he has had bad luck and flies off the disk.

Okay, this is feedback better directed at the developers of uBlock who are independent from Mozilla (who build and support Firefox).

I am just trying to help you to get the updated version of the add-on so that you can use YouTube.