store kit transaction error: "Cannot connect to iTunes Store" on ios 7 device

I had the same issue. Here is similar question I am getting error while requesting products from App Store for IAP

Try doing this:
1)You have to test on device
2)Go to setting -> iTunes & App Store -> and log out of your account.
Remove app from device and clean all data.
Make sure you have done all necessary steps for in-App purchase testing. Here is apple documentation
Run on device and test it.

If you having similar issue, please, check that you do not have expired contracts in itunesconnect.