Windows agent cant talk to server. MacOS OK

Hi, so have a new server running on centOS 7. Mac clients work fine. But windows clients is having problems.

From the event viewer on a windows client

Event ID 20

Service encounter error < Failed to load/parse last inventory state>

On server I see this:

192.168.xxx.38 - - [30/Jan/2018:11:35:37 +0000] "POST /ocsinventory HTTP/1.1" 200 103 "-" "OCS-NG_unified_unix_agent_v2.3.1"
192.168.xx.30 - - [30/Jan/2018:12:59:00 +0000] "POST /ocsinventory HTTP/1.1" 200 246 "-" "OCS-NG_unified_unix_agent_v2.3.1"
192.168.xxx.64 - - [30/Jan/2018:13:49:00 +0000] "GET /ocsinventory/deploy/label HTTP/1.1" 400 226 "-" "OCS-NG_WINDOWS_AGENT_v2.3.1.1"
192.168.xxx.64 - - [30/Jan/2018:13:49:01 +0000] "GET /ocsinventory HTTP/1.1" 400 226 "-" "OCS-NG_WINDOWS_AGENT_v2.3.1.1"

perl_module is enabled

Have the same problem if I run via HTTP or HTTPS

Windows ocs log

COM SERVER => Sending HTTP Post request to URL <http://xxx.xx.xxx.xxx/ocsinventory>
    COM SERVER => HTTP Post response received <HTTP Status Code #400>
    COM SERVER => Cleaning cURL library
ERROR *** AGENT => Failed to send Prolog <HTTP Status Code #400>
AGENT => Unloading communication provider