DIAGNOSIS A blockage in the airflow path between the robot's dustbin port and the dock's bag. The vacuum motor is running with restricted intake.
FIX Remove the robot from the dock. Check and empty the robot's onboard dustbin. Inspect the rubber flap on the robot's emptying port for obstruction. Remove the dustbag from the dock and check the dock's intake hole for a clump of debris. Use a long, thin tool to clear it.
IF THAT DIDN'T WORK The dustbag may be defective or non-genuine, not sealing. Replace with an official Roborock bag. A torn internal hose in the dock is also possible.
HEADS UP Running the empty cycle with a major blockage can overheat and burn out the dock's vacuum motor. Stop trying once you hear the loud, ineffective noise.