Clients geting offline every week

Hello

I have 5 server endpoints in management console and those servers are getting offline every week . After I rebooted smc services everything back to normal but they change status to offline few days after. Those servers are email servers and HT/CAS server and they are conected to Symantec mail security server .

How and where I can check why Symantec av on those servers lost connection every week ? Symdiag don't provide me this information .

Best regards