Yesterday the guys at Garmin have updated the Garmin Connect website, which looks nicer : ) but is also using a different login procedure. As I've already said a few days ago, Garmin does not have an official API to upload data to garmin connect. Things can break. This time you get a different error message ("Can't login").
To make it a little more challenging, it seems they're rolling out the update selectively. I'll try to find a way to make the login procedure compatible with the old version (for those of you who are still mapped on the old website) and the new.
Please, if you want updates on this, follow the sportablet account un facebook or twitter. I can either spend my time trying to fix the app or answering all the emails :-).