[VMware vCenter - Alarm Host connection state] Host connection state changed status from Green to Red

Hi All,

During off hours when the vRanger kicks backup on all the VM's then we get this alert ""[VMware vCenter - Alarm Host connection state] Host connection state changed status from Green to Red"""

I followed article http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1020210 however I did not help

Anything else that I can check here.

Thanks

Vaibhav