Can't log in but no error

When I try to sync one of my devices in Garmin Express it prompts me to enter my email and password. After I enter those and click "Sign in" the little circle icon spins for a few seconds and then the same dialog box appears again. There is no error about a wrong password or anything, it's just stuck. I am running version 6.21.0.0. How can I get past this screen?