Subscription works fine on iPhone, but not on iPad
I have bought an 12 month subscription code from a local department store. I entered the code into my iPhone, works fine but then when I go to my iPad and select "Restore purchases", nothing happens. I have tried to reinstall the application on iPhone and in iPad but nothing seems to help. Both devices uses the same AppStore credentials. I don't have the code anymore on me, so I cannot enter it on iPad. I trusted that ofcourse it will transfer via "Restore purchases".
Is this an error or should I have two subscriptions, one for iPhone and one for iPad?