The vShield Manager shows the error “Lost communication with ESX module”. This occurs when the ESX/ESXi host is running behind a vShield Manager and their time stamps do not match.
The vShield Manager creates a new certificate when it runs for the first time. If the time stamps are different, certificate verification will fail and the error message will appear.
This can also cause protected virtual machines (VMs) to appear offline.
To resolve the issue, make sure that the time on the ESX/ESXi hosts is in sync with that of the vShield Manager.
For more information, refer to this VMware article: vShield Endpoint reports the error: Lost communication with ESX module