We’re aware some users are still seeing "Server Error 400" when accessing YouTube on Android. Our teams are continuing to work on a fix and we’ll share updates here and in our help community below. Thanks for your patience!
goo.gle/3Wi4pnT
Update: This is now resolved! If you're still seeing a "Server Error 400" message on Android, please try uninstalling & reinstalling the YouTube app, or clearing the app's storage in your device settings (note: both will remove downloaded videos). Thanks so much for hanging in