DIAGNOSIS The cleaner head height is incorrectly set for your floor type, or the brush bar is jammed and creating excessive drag.
FIX 1. Check the cleaner head setting. The large dial on the head has multiple positions. For thick carpet, it must be set to the highest position. Turn the dial to raise the head fully. 2. Inspect the brush bar. Detach the head and clear any large debris, threads, or carpet fibers wrapped around the bar and axles. A bound brush bar creates significant drag.
IF THAT DIDN'T WORK The ball may not be rotating freely. Tip the vacuum back and inspect the main ball for debris lodged around its housing or in the soleplate. Clear any obstructions.
HEADS UP The vacuum is designed to be heavy on carpet for deep cleaning. Ensure you are using the 'Recline' button to tilt the vacuum into its operating position; pushing it while upright is not correct.