The requested URL "[no URL]", is invalid.

Hi, ive made a VS pointing to an external website (they want a 'nice' url..). However, i get an error, giving The requested URL "[no URL]", is invalid.

 

Here's what i'm trying: i have an external website for our company, https://cb.my.workfront.com/ Everyone can use that fine with no errors; it shows you a nice logon-page as per design. I've made a VS,accessed through https, certificate on it; whatnot; pointing to a pool with the above site as a member. When i access my VS, i get the aforementioned error. What am i missing here; when i open the url in a browser all goes well; but my VS does not like it..?

 

Thanks