Manual procedure followed?
1. see that all brackets and lift points are locked in (J-hooks can slip out sometimes). check that mower blades are not bent. Raise the four mower deck wheels to high position
2. adjust air to right pressure in all tires.
3. Set mower height adjuster to 2½"
4. 'level' on a flat surface, and set right to left 'level' first,
measuring at the tips. Make them both the same height
from the level surface within 1/8"
5. measure front to back on the right hand blade under the tip when it is full forward, and the same tip when it is full back. Adjust the front 'bail' so that there is 1/8" to 1/4" lower in the forward than in the back measurements.
6. reset the mower deck wheels so they are about 1/4" above the level surface.