Losing WMI Connections

Losing WMI Connections

I have over 50 workstations being monitored with EventLog Analyzer. Over time, workstations drop off with "Access Denied" or with "RPC Server unavailable". Since there aren't many changes to the workstations, I rather suspect Windows Updates have cause at least some of these.
I used to be able to use my checklist and/or script to reset machines that had dropped out like this.
Lately however, I'm not able to find a fix.
Tests with WBEMTEST fail at the same time. Because of that, Zoho says it's my problem.

Any suggestions? Here is the checklist:
NOTE: Each of the workstations WAS working.  And, half of them STILL work.  So, the settings seem to have been OK in the past.  I think I must be looking for something new.
                New to ADManager Plus?

                  New to ADSelfService Plus?