Log in ACP does not work after upgrade to 1.8.19

[Estabien]

Hi everybody


Im running MyBB1815 on a public server.
To play around and test, I put it all on a local Xampp installation and upgraded it to 1819

Since this was made I am not able anymore to do anything in the ACP

I am able to log in as admin and see the ACP landing page
But when try to move one -the Log In window pops up again.
dosnt matter if clicking the links or wright them manually
No possibilities to do anything in the ACP

I guess its something is wrong with the cookie path, but I did not find informations  where and what to change....
Maybe its something different

The original 1815 was installed local and everything worked fine.....

Is the above enough information? 
If not what is missing?
If yes-
What is wrong
What do I have to edit where??

Thanks for the help.
E

[Ben]

It does sound like a cookie issue. Could you post your cookie settings here along with the url your board is installed on and we can check them for you?