The reasons why the heated bed cannot be heated up are varied, please follow these steps for troubleshooting:
1. Make sure all cables are connect properly and the heated bed is intact, especially the thermistor under the plate.
2. Update the firmware to the latest version: https://forum.snapmaker.com/t/downloads-and-updates-for-firmware/1467/9 and start a new printing. Please check if the printer could work properly now.
3. Generate a new Gcode file in Custom Mode, and do not click "Has Heated Build Plate".
Start a new print and check if the printer could start to work now.
4. Could you please test the resistance value of the heated bed by a multimeter?
Please fill in the warranty request and let us know the resistance between 4th and 6th pins. We will provide a solution to you once the problem is located.