How to use HOT ATGM on RakJPz 2

Quite simply, how to use these missiles? Whenever I fire them they always head straight for the ground or simply don’t follow the mouse. I have used the Milans on the Marder and they just simply followed the center of my mouse cursor. How do these HOT missiles work? I want to also say that sometimes (on very rare occasions) the Milan also heads straight for the ground when firing, but the HOT is much more common.

I tend to aim my mouse up so the missile goes upwards before pulling it down on a target since most early missiles are slow