Logon to admin console failed

Sorry, but I´m new in asterisk, so my question seams to be very easy…

I´ve installed AsteriskNOW and logon with my admin account - everythings works well.

I´ve logout and try to relogon but I will automatically logout after a few seconds.

I will see for a few seconds the complett Navigator and without doing anything I´m logout.

I try different browser, delete the complette cache and restart also my asterisk system - no change.