Were you trying to cut the crown upside down and backwards, kinda nestled up against the fence?
Here is a different technique. It may sound complicated, but it really is the easy way for standard crowns:
Check it out, I'm going on the assumption that you have a duel bevel miter saw. Take the crown and lay it flat on its back on the saws table, right side up. You want to swing the miter, on the front of the saw, to 31.62 degrees. Next, lean the bevel over to 33.85 degrees on the back of the saw. Most saws have a detent or a least a reference mark on those settings specifically for this application.
This method eliminates the upside down and backwards confusion, and all the aggravation of trying to get a long floppy piece of crown nestled up against the fence just right.
Good luck, OP.
EDIT: For clarity.
EDIT 2:
Here is a short vid.