This error is generated when launching the Vault client from a shortcut and the shortcut Run property is set to Minimized or Maximized.The server connection class was not initialized. Call InitService before performing other network operations.
To access and change this setting, right-click on the shortcut icon and select Properties. In the Shortcut Properties cllick on the Run dropdown box to select "Normal Window."
Now you should be able to run the client properly and connect to the Vault Server.