I have also been having problems logging into YouTube with the same results. I click on "Sign In" and for a fraction of a second I can see the Google Sign-in page but it disappears and just redisplays the scree I came from. It's been this way for the last 2 updates. I even completely removed the product and re-installed it only to wind up with the same issue.
ChristmasRose
Could you please try it again, and this time, video-record your process to show us?
Please provide the StreamFab.log file too, thanks.