Product and version FileMaker Server 16
OS and version Mac 10.12.5
Browser and version (for WebDirect only) Firefox 52.2 ESR
Hardware MacBook Pro early 2011 (2ghz core i7, 4gb ram)
Description In the Server admin console webpage, the Status section shows "0 Total User Connections clients connected" (sic) followed by "0 FileMaker Pro" regardless of the number of FileMaker Pro clients connected. If you go to Activity/Clients, you can see that some users are connected. The 0's persist even if the clients have been connected for a while, even if you switch to Activity and then back to Status, so it doesn't seem to be a refresh or timing issue.
How to replicate With FileMaker Server installed and set up, connect to a database (the sample database is fine) from a different computer running some version of FileMaker (e.g. Advanced 16, client 14, whatever.). On the FileMaker Server computer, open the Admin Console and look at the Status screen. Observe that it says there are no client connections. Then go to Activity/Clients, and see the client connection you made. Switch back to the Status screen and see that it still says nobody's connected.
Workaround (if any) Just ignore the Status screen and look at the Activity screen instead.