Why won't my iPhone 6 on iOS 9 or my iPad mini on iOS 9 connect to the App Store, iTunes Store, or register my Apple ID?

I was playing a game on my iPad and wanted to purchase some bonuses, but when I tried to, the app said it couldn't complete the purchase. I then went to the App Store and logged out of my account to try to log back in, only to have a pop up saying "Cannot connect to the iTunes Store". I turned my iPad off and on, twice, only to see the error wouldn't fix itself. Wondering if this was a problem with just my iPad, I also tried it on my phone, only to get the same error.

Both devices are updated to the newest iOS 9 version and I haven't noticed this problem until today.