with a recent SU subscription licence tied to an email address (and not the discontinued classic licence w/ serial data): if resetting all devices via the Trimble AMP ("My Products > SketchUp Pro > ...") as well as logging out, closing/restarting SU, logging in fails, you may want try to delete the according SU license status file "login_session.dat" from:
• Win:
C;\Users\<User>\AppData\Roaming\SketchUp\SketchUp 20##\SketchUp\
• Mac:
~/Library/Application Support/SketchUp20##/
("Finder > Got To...")
w/ the recent user name for "<User>" (Win) and the appropriate version numer for "20##"