This is what the rockfax app says to me when I try and restore purchases or make a purchase. Using iPad Air 2, don’t have this problem on my iPhone. Tried reinstalling the app to no avail, just means I now have no guidebooks on the iPad can anyone help?
This seems to usually be something that goes wrong on the device, but in Apple’s frameworks. Although I think that error message may get returned for several discrete errors, including Apple’s server being down, which adds to the confusion.
Generally you can fix it by rebooting the device. If this doesn’t work, there are a load of fixes people claim may work that you can find by doing a google search for the error message.
In the coming months we will be moving away from using Apple for content delivery, which will completely remove these issues.
I’m sorry I don’t have a better answer for you. Please send me an email at firstname.lastname@example.org if none of this stuff works.