I am working on adding In-App purchases to my app.
I am able to receive the productsRequest:didReceiveResponse method, and receive the array of products
I had the same error, but the problem was not exactly the same. Maybe usefull for someone:
I inserted an external file in the structure of my app. The reason why I did this is because in production, I insert this file dinamicaly from a server, but in development I thought it was faster to use an app called iExplorer to paste this file. I have done this is the past and I didn't have this problem. But in the last few days, if I paste this file directly using iExplorer, my app returns the error: "Cannot connect to iTunes Store". (in spanish: "No puede conectarse a iTunes Store").
I think that it is because this time I inserted the file inside the .app folder. So this makes me think that if you modify your .app folder in any way, the Codesignature breaks and the link with the iTunes Store stops working directly.