Please power off the machine, then manually pull the Z-axis belt to position the platform in the middle of the Z-axis. After the machine is powered on and reset, check if the diagnostic interface on the panel(as shown)

Note: The interface displayed may vary between different models.

Under normal circumstances, when no material is detected, the Z Limit (or LmtU-) is blank. 

• If there are no materials within the sensor's detection range, but the panel's diagnostic interface indicates that the limit switch has been triggered, the sensor needs to be replaced.
• If the Z Limit (or LmtU-) is blank, but the platform has been continuously declining when focusing, restore the factory settings(click).

If the issue cannot be resolved, please contact customer service for assistance.