K8400 loud noise when auto home! how to correct?

I’m in the calibration stage. After uploading the correct firmware, and restoring failsafe. I selected “auto home” option (as instructed), the extruder moved into the correct position, then began making an awful gear grinding sound. The stage wasn’t touching the nozzle. I also experienced the same sound when attempting to move across the x axis in order to calibrate the stage on the opposite side. And there was VERY little to no movement in that direction. How do I adjust? What needs to be adjusted? I quickly discontinued turning the knob as soon as I heard the noise for the second time. Any words of advice would be greatly appreciated, thank you in advance.

Are all of your small grub screws tight? Belts tight enough?
Are you hitting the pulleys before it finds the optical stop?

You should really post this in the Vertex area.
Anyway this sounds like an alignment problem.
Look in this link.