I installed Ubuntu 20.04 on a new partition less than a week ago. I have not yet gotten all the basic stuff to work. But now, from time to time, 20.04 pops up a small window saying "Authentication is required to run gvfsd-admin daemon". But even though I enter my Ubuntu password and press it will not go away. Not even if I press the Cancel-button. Which, by the way, is a bit difficult to do, because instead you activate functions in a window BEHIND the authentication-window(!!) The only way of making the screen usable again is to restart Ubuntu... VERY annoying!
This worked for me: