This will happen from time to time as google changes things with YouTube and only a few people hosting public servers, you kind of have to bounce around to what's working at the time. Some other things to try would be piped, newpipe, freetube, vacuumtube, etc. Personally I moved away from Invidious a while ago because of errant playback issues, I've found newpipe to be the most consistent.

Seems to be a thing that happens every so often for a few days at a time. I’ve used a handful of instances for a year or so and they’ve all had occasional hiccups. I’d hazard to guess that it’s just a blip…

Although the stability/reoccurrence of blips can depend on how proactive whoever’s running the instance is. (Assuming it’s something under their control too. Sometimes YouTube just borks things for everyone because borking.)

I continue to have good luck with FreeTube, FWIW.