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The sensor switch may be defective... or, the circuit board it communicates with, perhaps, is sensing or giving false indications (- that can happen, too.)
But, try turning Off the printer. Unplug it from the power. Leave it that way for at least 2 hours, to cool off and rest/reset. Then see if that clears the sensor error.
Let me know how it turns out, what happens, and I will continue to offer assistance.