Hi good day, I installed 4.0 when I connect esxi and I click on the console I get segiguiente reading "Unable to connect to the MKS: Failed to connect to server xxx.xxx.xxx.xxx: 902. As the basis?
I was having the same problem and the solution was what some other people posted before, I manually added my ESXi hosts and vCenter server IP addresses to the hosts file and voila it worked like a charm !!
In your DNS and Routing settings ensure that your Default Gateway is the correct default gateway. A lot of times when you set a gateway for a VMKernel port this will override the mgt network gateway and your end up with this particular scenario where vcenter sees everything and communicates just fine, but MKS doesn't work and you can't ping the host because it is trying to send packets to your storage network.
This usually a DNS/name resolution issue. Ether put the esx server fqda into dns or put the esx server into the host file of the client. That should fix it.
Check your DNS settings on the host as well as on the DNS server. There is a good chance the incorrect IP address is associated with the host name on the DNS server
I solved my issue by checking the Subnet. My subnet was 255.255.0.0, I changed it to 255.255.255.0 on the management network.