FortiClient 5.4 Says Antivirus While Windows Says It Is On

I have business that has FortiClient clients running on their Window 10 Pro desktops. I inherited this system to support.

I have been told that in order to get support I need to provide the serial number of the EMS or FortiNet Server. I cannot find either of these on the network. Each of the clients has its own serial number.

On only some of the machines, FortiClient will send a message multiple times per day saying the antivirus software is off (as is Windows Defender antivirus). When I look at the FortiClient it is active on those computers and Windows Settings tell me it is on.

There was a old thread about something similar thing but the resolution (remove/reinstall) did not seem to work uniformily for the several people that were experiencing the problem.

Any help would be appreciated in either clues on where to look for the "server" (these are just networked together desktops; no Windows Server) or how to stop the constant messages that pop up that are driving the users crazy.

Thanks!