I'm no expert but,
in looking at your pictures, I think the mast has been pushed too forward onto the base and something, like one of the halyard exit sheaves, is butting into that piece on the mast step preventing the mast from going any higher.Position the mast so the its bottom is directly above the aft edge of the mast step. You will need to maintain this position by having someone hold the mast as it is raised. In essence, make beleive there is a hinge affixed to the mast step and the bottom of the mast and you are raising the mast up on that hinge.