I have got the same error message as in discussion 2007405:
"Unable to connect to the MKS: The remote host certificate has these problems:" 
The "problems" are not specified. The above mentioned solution to create new certificates does not help. At least not without rebooting the host.
Additionally as I am not using a vCenter Server I can not "remove the Host an re add it"
Until yesterday everything works fine. There was not reboot neither on the host nor on the running clients.
The message is the same for all running clients. The clients seem to be healthy as far as I can contact them via ssh.
What to do? ... just reboot the host?
Klaus