X axis Jams when retun to Zero and at Rapid speeds

Hi All, brand new to CNC. Just completed the assembly of the new Longmill MK2. At first X axis was jamming intermittently at normal speed now works okay. It still jams intermittently at Rapid speed and always jams when going to X zero. Swapped out stepper motors, no change. Lead screw turns freely by hand, the backlash nut seems fine.
Any help would be greatly appreciated.

Hey Shawn,

Welcome to the dungeon. A good place to start when having trouble is at the trouble shoot page sienci has that covers a wide range of topics you might run into. If your problem isn’t fixed there, you at least pick up a few features, settings, tips 'n tricks for future use.

Never hurts to start here.