If you close your client and re open it, then it might work. at least when i get failed to verify username. i think Microsoft requires the mine craft game to be closed and re opened every 24 hours or so.

some times i have had to log out and log back in. in the minecraft launcher. but it has been 2 hours so maybe you have already tried these two things?

i do know some times mine craft authentication servers go down and then players cannot have their usernames verified. but i think that is a different error message.