A changed or expired ESX system password is the most common reason for an ESX system to stop collecting data. Verify that the username and password entered for the ESX systems is correct and, if necessary, update the Configuration Update Gatherer and Platform Performance Gatherer services to reflect the new authentication information.
If the problem persists, take the following steps:
Drill down to one of the impacted ESX hosts by clicking on the Services tab from the left menu and selecting the Manage Services link. Click the Configuration Update Gatherer link and click on Test Service Monitor.
Contact uptime Support and provide the full output of the test service instance.
Repeat the above steps for the Platform Performance Gatherer.