XF 1.5 Problems with xenforo Movement and login on nginx


Hallo there!
I have some problems moving my xenforo local Installation to a server.

I setup a xenforo with plugins and theme localhost and moved the database and Filesystem to a server on Debian 9 with nginx and php7.1 (local I use apache and php7.1) and now my loggin get canceled. Also, I login on my forums and immediately get logged out.

Does anyone know how to fix this error? The Error Log says nothing. All required php Modules are installed and nginx on default configuration.