Is there anyone with the same problem we're experiencing below?

6 Windows 7 clients and 1 Windows XP client (10.2.2)

All 6 Windows 7 clients quit communicating with the server after a while.
Last contact with server time stamp doesn't change on both the client and
server. Next contact with server does, but the client doesn't refresh. If I
try to remote control, I can't. If I assign a new bundle, it doesn't work.
However, I can login to the Zen agent.

I can unregister the client locally and reregister and the client will
communicate with the server for a while and it will then stop communicating
again after several hours or couple days.

All but the sole Windows XP client are having this issue. Windows XP client
is also the first client registered in the server.