[2020] Error starting uplay launcher

Today, after doing a league mission, the video of the hunt appeared infinitely. It couldn't be canceled. I couldn't go to the menu either. I just keep pressing ALT + F4 to quit the game. When I did this I could not re-enter the uplay ... the legend appears that the connection was lost. I tried everything but there was no solution ... I don't know why. I even installed windows again, but the problem remains. My account has no problem, since I can log in here and in the account settings through the web. Please I need help as I can't play any games.