Hi Poldi,
Sorry to hear about your issue! I just checked our backend and I can confirm that I’m seeing several incorrect logins. Both your e-mail address and your username can be used for login, so the only difference should be the password. I obviously don’t know what your password is, but if it contains \ or % characters, you might want to change it – while they work fine in the frontend, they aren’t accepted by the backend. This is something that only recently surfaced, and I’m still in a process of resolving it.
If you had any of those in your password and after changing it you are still having issues, or if you didn’t have any of them please let me know, and I’ll follow up via e-mail.