The VMware Knowledge Base provides support solutions, error messages and troubleshooting guides
Canceling a Connection on an Added but Disconnected Host Removes That Host from VirtualCenter (1833)
If this happens, re-add the host.
To correct this, upgrade to VirtualCenter version 1.3.1 or later.
Request a Product Feature
To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.