Unsafe Sensor Position

Check if the nozzle has residue. To clean it, pick up the nozzle through the printer menu. Then, heat it for three to five minutes at 250 °C, as the remains of the filament must be warmed up slightly so that they can be removed more easily.

Use a small brass brush to clear away any old plastic stuck on the nozzle. Avoid contact of the brush with the hotend cables, as this could cause a short circuit.

Tool offset calibration

Make sure that the filament is unloaded before the calibration process.

Go to the printer menu in Control -> Calibrations & Tests -> 12. Tool offsets calibration and redo the calibration.

Reduce vibrations

Any vibration propagated to the surface under the printer, or an unstable surface under the printer, might cause a false reading on the load cell, triggering the homing error.

For example, a printer that is in operation next to your printer can cause vibrations that are propagated to it, potentially causing a tool offset calibration failure. In that case, stop any printers next to the CORE One with INDX, and reattempt the calibration.

A possible solution to dampen the noise and vibration of a printer is to add some additional padding underneath the printer.