Good news everyone!
For those still having issues logging in: Just log in here and grant the system ~3 minutes to sync your data to the world server. (Same for password changes and rewards!)
So, the dust has settled after last weeks fight for a working server. For those who missed out on all the action: Our host decided to disable a feature that we used to verify login data. That is, before we actually had a working alternative up and running. Long story short: We're back, stronger, better and faster!