Monitoring error occured so frequent

[Freman]

We are monitoring 9 SQL servers but I found some of them keeps getting the following errors some days ago:
Monitoring error (SQL Server data collection)
Monitoring stopped (host machine credentials)

Yesterday afternoon when this error occured three times I checked the event log and found this exception:
15 Oct 2012 5:20 PM WMI OpenNamespace: root\cimv2 Cannot connect COMException Call was canceled by the message filter. (Exception occured at HRESULT: 0x80010002 (RPC_E_CALL_CANCELED))

I have did the testing data collection methods which the Red Gate suggests and checked the network,AD,firewall(always closed),necessary services,etc.
Sadly,I found nothing at last.Can anybody help me with this?

[chriskelly]

The definition of these alerts are:

Monitoring error (SQL Server data collection)
One of the following conditions applies continuously for 2 minutes:
Problems with WMI
Problems with the remote registry
File sharing issues
SQL connectivity issues

Monitoring stopped (host machine credentials)
SQL Monitor is unable to collect monitoring data from the host machine because the credentials supplied to connect to the machine are invalid or lack permissions.

In the case of the first alert, once the condition which caused it to be generated are no longer present the alert will change from Active to Ended. So it looks like you have a problem with the Windows Management Instrumentation protocol which SQL Monitor uses to collect some data from the monitored host machine. Please take a look at the document links which are listed in this document towards the end of the section marked Testing WMI.

The second alert can be a little more difficult to pinpoint. How long does it stay active for? how often does it occur?
_________________
Chris Kelly
Technical Support Engineer

[Freman]

Hi Chris,
The two Alerts disappeared some days ago when I reinstalled the Windows OS & SQL Monitor Software.

However,thanks you very much!