Q: I can buy stuff in iTunes and the AppStore, but no in-app purchases on any app on my 64gb iPad air 2

I Tried with "on", with "off" - it doesn't work !!! I tried everything - restore, log out ... I have my old iPad with same Apple ID and I can buy everything , but not on iPad Air 2

It is say - cannot connect with iTunes - contact Apple support / iTunes/ ww . But my I tunes connected and I can buy stuff, except an in-app purchase. I did log out from iTunes and tried to buy again. It is ask my apple id and password and than ask " you want buy ... for $..." I press " yes" and it say " contact apple support"

P.S. : Sorry , my English bad))) I'm from Ukraine and just one year live in USA.

Thank you, I already sent message to support and they sent me link , and I did everything but nothing help .   Yes, I buy from U.S. App Store .
I see many people have same problem and apple support didn't help at all .

iTunes: Possible iTunes Store errors - Apple Support
I set appointment with local Apple support service for today . Hope they will help .

Also I had advice  -  check internet , restore , back-up , log out and try to buy again... I went to store where I buy my Ipad and they tried to fix , then they exchange my ipad and another has same problem . So , they told me go to the local service and if they could not help I can back Ipad to the store . I have 4 apple ipads in my family ( USA) and all of them set up with same Apple Id , but only with this one I cannot buy  in-app purchases.

Thank you very much  for your help ! I hope I will get help today .

I fix it!!!!!!!!!!! I so happy!!!!!!!!
Local apple support service sent me this :

Before You Come In           Back up your data.                          Please be sure to back up the data on your iPad — either on your computer or using iCloud.* Learn how to back up your iPad                 To service your iOS device, Find my iPad will need to be temporarily turned off. In order to turn off Find My iPad, you must know your Apple ID and Password.             Update your software.                            Many issues can be resolved by updating the software on your iPad. If you’re on iOS 5 or later, you can update over Wi-Fi or by connecting to iTunes on your Mac or PC. Learn how to update your iPad

And I follow Back up and restore your iPhone, iPad, or iPod touch using iCloud or iTunes - Apple Support and now I can buy in -app purchases !!!

My previous mistake was that after back up I restore my Ipad as "new iPad" instead restore as "Icloud back up" . I saw many people have problem with purchases and I think maybe this will help somebody.