This issues happened in iPad Air 2 after updating to iOS 8.4. iPad Screen Rotation lock not Working.
Before following fixes:-
- First backup your iPad using iCloud or iTunes.
- Check your iPad still under warranty or not. If your iPad under warranty, then contact nearest Apple care.
Fix 1: Turn Reduce Motion off
If the Reduce Motion future already activated, then turn it Off. Navigate to Settings -> General -> Accessibility, find Reduce Motion and swipe it off.
Fix 2: Restart iPad
Press and hold the iPad Power button and Home button until it restart.
Fix 3: Check Orientation lock is activated?
Make sure orientation lock is deactivated. Go to iPad Home screen. Swipe from bottom to top of the screen to access Control center and check the orientation lock.
Fix 4: Reset All settings
Go to Settings -> General -> Reset -> Rest All settings. Then check your iPad Air rotation issue.
Fix 5 : Contact Apple care
Check your iPad Air warranty status. Take your iPad Air 2 nearest Apple care.
Also try to restore your iPad. Suggest your own solution to fix this issue.