If you move your 3D printer or CNC machine manually using G commands and at some point device stops moving, it might be due to hitting software endstops.
Marlin has the ideas of software endstops. This is an additional security measure that is designed to protect the printer from exceeding the axis limits. Axis limits are taken from [XYZ]_MIN_POS and [XYZ]_MAX_POS parameters.
They might become problematic in some procedures like for example bed leveling or any other operations during which we consciously need to exceed the axis limits.
Good news is that you can easily turn software endstops off using GCode.
Turn Software Endstops Off
To turn software endstops off execute command M211 with parameter S0
M211 S0
In return you will be given the current state of endstops and min/max values for them:
Soft endstops: Off Min: X-33.00 Y-10.00 Z0.00 Max: X220.00 Y220.00 Z240.00
Turn Software Endstops On
Similar, to turn software endstops on execute command M211 with parameter S1
M211 S1
In return you will be given the current state of endstops and min/max values for them:
Soft endstops: On Min: X-33.00 Y-10.00 Z0.00 Max: X220.00 Y220.00 Z240.00