How to get Shopping Sources in Bing Visual Search

Question

I am trying to use the Visual Search API to get links to where a certain product in an image is being sold. The ShoppingSourcesAction would be perfect for this. Unfortunately, the JSON response never contains this action. I thought it might have been as a result of my image, so I tried very clear images of well known products (like a cheetos bag, lays potato chips, coke, etc.) in order to see if that was the issue and still got no ShoppingSources. When I try these same images on the official site, I am able to see shopping results (I understand that the site could have different versions or configurations but ShoppingSources should be availible on the released API too). I also tried adding some invoked skills (the code to which i've inserted) to the knowledge request and this did change the response a bit, but still no ShoppingSources (I get all of the other ones though). I'm pretty much just wondering what could be the issue. I really don't think its the images themselves. Could it have something to do with my subscription? Any help would be grealty appreciated. Thanks!

"invokedSkills":[
         "ImageById",
         "BestRepresentativeQuery",
         "ShoppingSources",
         "PagesIncluding",
      ],