I was trying to contact my server and the following error appeared:
Starting OCS Inventory NG Agent on Monday, August 06, 2018 10:22:32.
AGENT => Running OCS Inventory NG Agent Version 188.8.131.52
AGENT => Using OCS Inventory NG FrameWork Version 184.108.40.206
AGENT => Loading plug-in(s)
AGENT => Using network connection with Communication Server
AGENT => Using Communication Provider <OCS Inventory NG cURL Communication Provider> Version <220.127.116.11>
AGENT => Sending Prolog
ERROR *** AGENT => Failed to send Prolog <HTTP Status Code #500>
AGENT => Unloading communication provider
AGENT => Unloading plug-in(s)
AGENT => Execution duration: 00:00:00.