Garmin Express - "invalid sign in"

Dear all,

I tried to log in my Garmin via Garmin Express and get the error "invalid signi" under both Windows 11 and Mac OS Sequoia 15.5.

I checked that the credentials are correct - I can log in via the web browser, no issues at all? 

Can anybody tell me how to solve the issue. There aren't too many settings option under Garmin Express ;-)

Any help appreciated. Thanks!!!