Agent does not connet

Hi,

I try to connect an Agent on Win7 Workstation to my OCS-Server ( Debian 8.7), same Version of Agent and Server (2.3.0.0) . Connection fails with Error.

Already red the entries in this Forum but found no solution...

The Agent produce an Inventary file I can import manually in the Website but there is no connection. I get this Logfile:

Starting OCS Inventory NG Agent on Monday, February 06, 2017 11:47:50.
AGENT => Running OCS Inventory NG Agent Version 2.3.0.0
AGENT => Using OCS Inventory NG FrameWork Version 2.3.0.0
AGENT => Loading plug-in(s)
AGENT => Using network connection with Communication Server
AGENT => Using Communication Provider <OCS Inventory NG cURL Communication Provider> Version <2.3.0.0>
AGENT => Sending Prolog
ERROR *** AGENT => Failed to send Prolog <HTTP Status Code #400>
AGENT => Unloading communication provider
AGENT => Unloading plug-in(s)
AGENT => Execution duration: 00:00:00.

Anything else you need to know to help me, please?!?