Apple’s 3D Touch feature is very helpful and interesting when it works, but many iPhone 7 users are complaining that the feature stops working all of a sudden. Sometimes, the problem goes away on its own, but for other users, it seems to stick around till the phone is restarted. So try restarting your device as the first solution to fix this problem.
Also check if your screen protector is causing the problem by using 3D Touch after removing the protector. Clean up the screen and try to use the 3D Touch feature and see if it works.
Some users found that the problem was that the feature was switched off on their device. If this is the case, then you can switch it on by
- Going to Settings
- Tapping on General
- Going into Accessibility
- Looking up 3D touch and ensuring that the feature is switched on. You can also check for the sensitivity of the touch to make sure that it responds effectively to your touch.
If nothing works for you then you can visit an Apple Store to find if hardware problems may be the reason for the phone’s touch problems.