unable to login / infinite login loop

This is a unique problem that i haven't seen before (and is baffling me). Out of no where, my website for no obvious reason started to make it not possible to login (including me). ( www.starcraftuniverse.org ). There was a timeframe i wasn't on the website until i noticed it(2-3 weeeks because of finals) yesterday. Therefore, no upgrades were done, or changes to the files so i am unsure what could have caused it. No Errors in the console. I upgraded to the most recent version today and still the same problem.

Characteristics:
-If password is wrong it redirects to the "wrong password" page.
-If password is correct it reloads the main pages but does not log you in. (putting you in an infinite loop of not being able to login)
-Reseting password does nothing
-Affects all account from the main admin account to the normal user account

What could have caused it:
-No Idea: Was away from the site for 2-3 weeks and i come back and this is a problem.
-Tried upgrading to the most recent version today and still the same problem.

I have the same problem.

New install 1 week ago, No changes file, only the language Phrasen.

http://www.phpfox.com/kb/article/138/enabling-debu... enable debug server method and post errors please.

ok i have enable the debug server.

I can not detect errors.

My Domain is.
kreativquiz . de

Best Regards
Alex

Did you change user settings for can stay logged in to the site?

No, I do not have.

cookie name I have given "kreativquiz".

And after doing that, you cleared your browser cache including cookies? You also have enabled cookies right?

both yes.

will look when I get off work.

Thanks for Help.

Table optimizes and fixes no solution of the problem.



Now install everything new again.