Please post in International > Streamfab.
Also, it still helps if you post original language then translated to English after.
I don’t know of any issues with YouTube.
(1)Did you delete the streamfab temp folder, with streamfab closed, then try?
(2)You did not say if it’s 6266, you did not say what video(s).
(3)Also, maybe attach your streamfab.log?
—If you do that, first delete the streamfab.log, then go to the trouble video, when the issue happens, close SF.
—Then attach the streamfab.log.