I’ve had this on freetube on desktop happen constantly over the last few months. Seems to happen after watching a certain time length on YouTube and then blocks me from watching on freetube or using YouTube embedded. It tends to come back for me after a few hours. All its made me to is cut back on my youtube subscriptions and watching by nearly 90%
Freetube, invidious and vacuumtube all stopped working for me. Getting error messages in freetube that looks like its getting xml when it expects json
It’s been broken for a few weeks. They’re aware but I think it’s an upstream fix they’re waiting on. I’m the meantime I use yt-dlp.