First things first, there are many questions similar to this, I know, but I tried all of the answers and they don't seem to be working and I think mine might be a different case (I THINK)!
I recently updated to iOS 5.1 and Xcode 4.3. All my iAds work perfectly on the Simulator, but not on my iPhone. Just to confirm my case, I ran some of my older apps, again, they all work on the simulator but not on the phone. They all call the didFailToReceiveAdWithError
method.
Again to double check, I downloaded Apple's iAd Suite and tried to run them, same thing, fine on simulator but not working on the phone.
Although the iAds from my previous apps that are on the appstore seem to be working fine on my phone, I'm not sure what the problem is.