Having the following error while trying to open the console of your guest VMs?
Unable to connect to the MKS: Login (username / password) incorrect
This is happening because the communication between your client computer and your vSphere host isn’t working properly.
The main cause for this would be that the ports required for the console are blocked in some way (either blocked by your LAN or workstation but more likely on the host side).
Make sure that the host firewall is not restricting the connection :
Configuration tab > Security profile > Firewall > Properties…
The ports required for the console are (tcp) :