Servers randomly losing CPU and Memory monitoring stats

Servers randomly losing CPU and Memory monitoring stats

Hi,
 
Just checking if anyone has come across this issue. We have recently signed up to OpManager and spent some time getting all our servers added and monitored. Yesterday i noticed that about 20 of our monitored servers no longer showed stats for CPU and Memory monitors (see attachment).
 
I can confirm the monitors themselves for both still definitely exist under performance monitors and that the credentials used (WMI protocol) is passing the test. The credentials used had previously worked and continues to work for other uneffected servers.
 
I have tried going into the edit properties for the CPU and Memory monitor and selecting the 'Test Monitor' button but this fails with 'Monitor did not respond to the test request'.
 
I have tried pushing down the template to the server again but this has no effect. Even unmanaging and remanaging the server has no effect. So far the only way i can get it to work again is to delete the server from OpManager and readd it again. This obviously removes any previous stats for the that server and is not a workable solution. I did this for the 20 odd servers yesterday in the hope it was just a once off blip but today i see one of the server that previously did not have the problem is now suffering from the same issue.
 
Any help from community members or OpManager support (if they respond to forums) would be greatly appreciated.
 
Thanks!

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