Unable to connect to the MKS: Login (username / password) incorrect

• Open /etc/vmware/config with a text editor.
• Add this:  vmauthd.server.alwaysProxy = “TRUE”

Check your firewall config/network setup.    This error is caused by your vSphere client not able to communicate with the ESX/ESXi host directly.

All “Unable to connect to the MKS:” errors are network issues.   Do not be fooled by the mention of certificate issues…

ESX/ESXi 4.0 /etc/vmware/ssl/
vCenter Server 4.0 C:UsersAll UsersVMwareVMware VirtualCenterSSL
For Windows Server 2008, C:ProgramDataVMwareVMware VirtualCenterSSL