"An “X” in the middle of the reticle indicates the aircraft is below the set Minimum Range
(MRS/MRC) altitude."
pg. 374 from the manual.
ttp://srv4.files.eagle.ru/dcs/manuals/DCS-A-10C_Flight_Manual_EN.pdf -keep trying to embed the manual in the post, add a H.
try flying level and tilting the nose of the aircraft down to see the reticle, get the hang of seeing it go from ready, to a X. If you using LGB you can still release and lase.