Vmware esx cannot synchronize host

I had this problem today.

Using this diagram I noticed the VPXA service talked to vCenter Server.

from http://www.vmlab.com.pl/host-fails-to-update-information-with-the-error-vmware-esx-cannot-synchronize-host/

Then I read this post 

So I restarted the services on the host and after 2 minutes the services sync-ed up.

We found out that there is a problem with the DNS server. We pinged the node1 in the cluster by the ip address. The ICMP returned with no problems. When we pinged with the node's hostname the ICMP packets we have 50% failure. We turned off one of the DNS servers and the ping to the hostname returned 100% successful.