DIAGNOSIS You're seeing a solution delivery or recovery failure. The primary culprit is almost always an overused or clogged brush roll.
FIX Immediately remove and clean the brush roll. Unplug, flip the machine, release the two latches, and pull out the brush roll cage. Remove the brush roll itself. Use scissors to cut away all hair, threads, and debris wound tightly around the ends and bristles. Rinse the entire roll and its cage. Let them air-dry completely before reassembling.
IF THAT DIDN'T WORK The problem might be in the suction path. Check the nozzle for blockages where it meets the machine, and ensure the dirty water tank filter (the gray foam one) is rinsed clean and completely dry before reinserting.
HEADS UP Never reassemble the brush roll or use the machine with wet components. A damp brush roll will instantly re-clog with debris and create terrible suction.