Vibrate and haptic feedback not working on my new iPhone 6s
This happened twice already,my iPhone 6s I've just noticed that the vibrate or haptic feedback feature is no longer working on my iPhone 6s. And I tried putting the phone on silent and utilising the 3D Touch feature, but no luck. The 3D Touch does allow me to drill down into the features, but no haptic feedback.After I restart it's working normal again. Any clues? Is this a hardware issue or software issue
iPhone 6s, iOS 9.3.1