Thanks for your patience, the 500 error is now fixed!https://twitter.com/TeamYouTube/status/980889488531521536 …
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Try clearing your browser cache, cookies with these steps:https://goo.gl/j58cEL . Let us know if that does the trick!
I already tried all those steps and the issue is still not resolved. I am using Google Chrome (where this error often pops up) but it seemingly doesn't appear on Firefox. Something must be wrong with my browser then. It should be fixed automatically soon, I hope.
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