We have an issue when trying to logon to LSD
:Connection Failed : object refrence not set to an instance of an object
I'm not sure if this is your issue, but ISD is very picky about the server string, and it doesn't necessarily throw a helpful error or any error. Sometimes it just locks up.
The server string needs to be "host:port" - in our case "ltmdev.simplot.com:1443". No "http" or "https". Be sure the SSL checkbox is checked if that's what you're using.