I see that you're having an issue with 3D Touch not working. I'd be happy to provide you with some information to help.
Let's start by having you restart your iPhone and test to see if the issue remains.
Restart your iPhone, iPad, or iPod touch
If after restarting the iPhone the issue still remains, take a look at this article that can help with adjusting the settings for 3D Touch:
Change 3D Touch sensitivity on your iPhone
Thank you for using Apple Support Communities.
Have a great day!