Firewalls can often pose a problem with the i Tunes Store.If you can access websites but cannot access the i Tunes Store, it is likely that firewall software is the problem.Some employers do this because they feel it increases productivity.If you are using Mac OS X, go to the Apple menu at the top left of your screen and select System Preferences.This also happened the day after I got my i Pad; in that case I had to do a factory reset of the i Pad's settings.Resetting to factory settings (not resetting data) didn't help at all this time.If your computer was provided by your employer, make sure to check with your desktop support staff before making any changes.
Strange enough, I started having these issues after the update, I never faced it with IOS 9.0.2. i Phone 6s, i OS 9.1 URL: https://discussions.apple.com/thread/7299239?
Let’s take a look at how to troubleshoot this problem…If you receive an error while trying to connect to the i Tunes Store, the first thing to do is just try again. I find when I retry the transaction a few seconds later, it works fine.
If you are using i OS or Mac OS X, simply try to purchase or download the item again.
Next, click on Security & Privacy and then click the Firewall tab.
You may need to click on the lock in the lower left and type in the administrator password to make changes.