When any image is clicked in my image store, the user can add that image to their cart.
When Jetpack is enabled in the plugin library, the user cannot add an image to the cart. Disabling Jetpack in the plugin library enables the user to add images to their cart.
I have tried deactivating each Jetpack module 1 by 1 and have been unable to identify any 1 module which is causing the problem. I then deactivated the whole Jetpack plugin in the plugins library and now users can add to cart.
Incidentally, my hosts have had me make this mod to my .htaccess file to enable Jetpack to get authorized.
I hope I've explained it well enough for you??