connection to the OCS server fails with the actual version of OCS.
current version of Win64 agent 126.96.36.199 (same issue with agent 188.8.131.52)
current version of OCS server 2.7
The log file of the windows agent contains the following message:
Starting OCS Inventory NG Agent on Sunday, April 5, 2020 06:00:32.
AGENT => Running OCS Inventory NG Agent Version 184.108.40.206
AGENT => Using OCS Inventory NG FrameWork Version 220.127.116.11
AGENT => Loading plug-in(s)
AGENT => Using network connection with Communication Server
AGENT => Using Communication Provider <OCS Inventory NG cURL Communication Provider> Version <18.104.22.168>
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.
Also in the apache log on the server you could the eror code 400
Some clients have an older version of the Windows agent (2.1.1.). With the older agent the communication with the server works.