X Axis Locked Up

I’m having an issue with the X Axis on my machine. Initially it was as if the step motor stopped working but come to find out, I had to retighten the set screw that connects the motor to the screw. Now it will jog back and forth at low and medium speed but will lock up again when trying to jog at high speed. Please help.

Thank you!

Hey Brett,

this reminds me of this