this case happened with me last implementation in more than one site but only happened with me in vmware vsphere esxi 6.0 U1 b all technical talk about this issue that i have DNS or Firewall Issue in my environment yes you are wright but not in all scenarios cuz if you implement vsphere 6.0 and you don’t have firewall between internal server and you are configured DNS so what the problem ??
the SSL certificates are updated by the ESXi host when connecting to the new vCenter Server. These certificates are used by the console and may not be updated with the virtual machine running.
- Power off and Power on the virtual machine.
- Migrate the virtual machine to another ESXi host using vMotion.
- Suspend and then Resume the virtual machine
for more info please read this KB