VMWare vCenter cannot contact the specified host error while adding host.
Please search VMware web site first if you get this error and if you haven’t looked to general solutions for this issue yet. You might have problems in your network configuration, DNS, IP or Lockdown mode might have enabled on the host. etc.
You may have latency issues if you still get this error and you believe your network configuration is correct.
In my case vCenter starts adding the host in retrieving mode, I can see it can communicate to my host on host’s events as well.
But if fails and gives the error below.
Cannot contact the specified host. The host may not be available on the network, a network configuration problem may exist, or the management service on this host is not responding
I found this solution at VMware web site (Alarms about the host connection state changing from green to red frequently occur (1020210)) and added
<handshakeTimeoutMs> 120000 </handshakeTimeoutMs>
between <ssl> and </ssl> in /etc/vmware/hostd/config.xml file, then restarted the management agents, it resolved my issue, hope it helps.