A Symantec Endpoint Protection (SEP) agent is unable to complete the registration process with its Manager (SEPM). It is possible to see it in the expected group but its status is offline.
Replacing the sylink.xml file, resetting the hardware ID or reinstalling the SEP agent do not help.
The SEPM and other SEP clients do not have any problem.
Packets capture shows that the SEP agent is properly sending the registration request and getting the confirmation of the same from the SEPM.
In the SEP client, under Help > Troubleshooting > Connection Status, this message is displayed:
Not connected.Error details:
This is a general error message indicating that communication with the server failed. Run the Symantec Endpoint Protection Support Tool (SST) to diagnose the problem.
SST report shows:
Connection status: Not connected.
Other:Error in registration response (8).
In the sylink.log, the registration fails due to ERR to query content length; differently from similar issues, there is a 200 OK confirmation here: