If you get a black screen when you try to connect to the console with the following error:
Unable to connect to the MKS: Failed to connect to server xxx.xxx.xxx.xxx:902
Then it’s likely that you have some network obstruction between your vSphere Client and the VMware ESXi host that the VM is running on. Check that port 902 isn’t blocked by opening a telnet session to the IP specified in the error on port 902 to confirm this.
For me, this was caused by a routing issue, but it’s also worth checking the firewall and any physical ports that are between the ESXi host and your vSphere Client.
PS: If you were wondering if MKS is some sort of special VMware technology used for establishing console connections… It’s not. MKS stands for Mouse Keyboard Screen 🙂