You may receive this warning message in vSphere client and most probably the Virtual machine console also won’t open.
To Fix this issue go to ESXi console ->
Config -> Defaults -> Security -> host.
Uncheck Config.Defaults.security.host.ruissl and click OK. Then go to the same setting and check the box and click OK.
after following above comments but problem still exist .
Still we are facing the same issue post done the uncheck and check the option.