Stuck at auth/login?to=/auth/check

when i try to login since two weeks i’m stuck at this screen.

when i login it reloads the page.

the password didn’t change and my password.
this is happening in another instance i installed for a friend a month ago.
how can i solve?

I experienced that as well once but cant remember anymore what caused it.

Did you verify that the dir permissions are all correct ?
Did you check your php error log?

Where you able to find that mystery bug?