Jens, is this account (the one you posted this thread with) your new account? Just to confirm, you could log in previously with the old account, correct? It takes some time (up to an hour) for the account information to be transferred between the main and dev servers, so if it was a brand new mentor account, it could take a bit to be available. We've also experienced a number of hiccups with people not being able to log into the Dev server recently, but they're generally short lived. Give it another try with your original account, please, and let me know if it works now or if you're still having problems. EDIT: You can also try clearing your cache and cookies if you're still having this issue. That seems to have cleared up the problem for most of our users.