Settings > Instance > Disable instance proxy.

LibreTube is meant to be used with a YouTube piped (which is a different thing than NewPipe) instance, which proxies the video stream. It’s very nice in theory, but in practice, the instances get blocked constantly. Disabling this option will make your device connect directly to YouTube (which leaks your ip address to YouTube) and make it work the same way NewPipe works

Yeah, works great when it actually does work. But pretty much never works when it’s supposed to. So I’ve been frequenting tubular more