Have a John Deere 5303. The arms of the 3 point hitch are stuck all the way up.
How I can fix this?

Implement Lock / Rocker Shaft Drop Speed Adjustment.
CAUTION: Excessive falling speed can cause damage or injury. The total lowering of the implement must
require at least two seconds.
The rocker shaft lowers faster when a heavy implement is attached. Adjust the drop speed button so that
be slow enough to be safe and prevent damage to the implement.
Turn the rock shaft fall speed knob (A), located under the seat, clockwise to reduce the rock shaft fall speed.
falling of the arrow.
Turn the knob counterclockwise to increase the rate of fall.
The drop speed knob is also called the implement lock. When the knob is fully screwed in, the implement
When the knob is fully screwed in, the implement will not lower even though the position control lever is fully down. Use the implement lock while
transport of the implement.