This prompt indicates that the hot bed is not heating as expected, possibly due to a hot bed heating element failure, wiring problems.
Check the heating element: ensure that the heating element of the hot bed is working properly and there is no obvious damage.
Check the wiring: Check the wiring of the hot bed to ensure that all connections are secure and not loose.
Check the hot bed heating element to ensure its normal function.
Check the cables to the hot bed to ensure that they are securely connected.
Restart the machine and observe whether the hot bed can be heated normally.