Help! Not all animations exported?

I’m working on a game that is going to be heavy with facial animation.
However, I seem to have a problem in exporting animations from 3ds max 2019 to UE4.
I separated the eye and the hair from the body.
The body and hair animation works just fine, but the eye animation just won’t work.
As you can see, there are only 3 morpher curves detected, which are all from the body.
The bones for the eyes appear, but the keyframes don’t.
What should I do?