Split from this thread.

Well I am trying using Windows Live Movie Maker as provided with Windows 10 build 15.4.3508.1109 and after I open the video file and sign into Windows Live and click on the Facebook logo I select a resolution (any of them give the same result) and it pops up a browser window of

Something went wrong and we can't sign you in right now. Please try again later

Which is about as helpful as a chocolate fire guard ... and it happens time after time after time.