Problem with animation (humanoid rig)

I'm using the free mocap animations available on the asset store and I'm trying to use the animation inside one of my animators. The problem is that when I play the game, the character with the animator plays my custom animations properly but when it switches to one of the mocap animation, the character doesn't play the animation. Despite that the issue occurs in gameplay, when I use my character in the animation preview for the mocap animation fbx, my character plays the animation perfectly. Is this problem related to my character's rig, avatar, or my animator?