Can't make login to sap portal.

Hello!

I need to acess to my sap portal but when i try it the only thing it do is a refresh ( like press F5).

When i enter a wrong password i get a error message that my user/pass is wrong. When i enter the correct user/pass only makes a refresh.

In logs i can't find anything.

Can someone point a possible cause of this issue ?

Is a solution manager with abap and java stack, Windows 2008 R2 SP1 and Microsoft SQL Server (10.50.1600).

Ask for more info if you need .

Thank you!