AIM-7 misses

[Tango777]

The AIM-7 Sparrow misses every time. I get a solid lock on the right TDI's radar page, in the hud the green dot is in the target box, the word "SHOOT" begins to flash, and then I launch the AIM-7. It flies toward the target perfectly and then about 0.5 nm short of the target the AIM-7 turns right, or left, or above, or below the target every time no matter the enemy aircraft type.

 

What am I doing wrong?