Good news: YouTube has restored all the video's on the Blender Foundation's channel.
Last night the Youtube Support team contacted Francesco Siddi by phone. As we understand it now it’s a mix of coincidences, bad UIs, wrong error messages, ignorant support desks and our non-standard decision to not monetize a popular Youtube channel.
Continue reading the full story with the entire background of what went wrong on Blender.org. The PeerTube channel will remain as a test, but the team is too busy to fully build that out right now.
Update: some people report still errors - according to YouTube it can take several hours before the changes are available everywhere.