Why is my screen not going black during calls?

I'm wondering if I did something wrong during my install. On my old screen it would go black during calls but after I installed the new display it won't do it, so for some reason there is an issue with the proximity sensor.

There is nothing blocking the sensor and it won't work even when I place a finger over the sensor. Everything else about my screen works just fine, front facing camera works, but the new proximity sensor doesn't work. Screen isn't cracked, not physical damage, nothing wrong with the package when it arrived.