My Dad's iPhone is still on iOS 9.3.5 and he's having a problem where he gets a "Cannot connect to App Store" error when going into the App Store. This disappears, but all the tabs in the App Store are blank, except the updates one, which populates normally. He can update apps. iTunes has the same problem. I've already tried signing him out of the iTunes/App Store and back in, but the problem persists. My Mom's iPhone (same model and iOS 9.3.5) works fine. Any idea how to fix this?