I was having trouble with this, and spent about an hour messing around with different settings before things ended up working. I was making changes to the type of URL, the URL itself, the authentication schemes, and the passwords secure/show boxes. Suddenly it started working, and I'm not sure why since I think the settings that worked were very close if not identical to what I had originally entered, as described in the help popup text that comes up when clicking the blue ? button next to the URL Live field.
Here's how my provider screen looked when it started working:
