ASI462MC

Has anyone had experience using this camera on a Lunt LS50Ha solar scope? I have not been able to get the sun into focus, even with the camera mounted directly onto the diagonal (without the nose piece) as someone had suggested. I simply run out of focus travel.
Using this same camera on an 8" Meade LX90, and using ASI Studio LiveStack, it keeps coming up with a message "cannot find alignment starss" even though there are plenty of stars in the frame. What am I doing wrong?