If the suction is ok, its probably due to hair being caught under the motorised head rotator.
# Take out the brush
# With a hexagonal screw driver head, not sure what size to be honest, remove the screw from the center of the rotator.
# Lever out the rotator.
# Use a pair of tweezers to remove any hair, you’ll be surprised as to how much there is.
# You may have to add a little grease
# Replace rotator, tighten up screw. Ensure it can turn manually.
# Test by attaching to battery and pulling trigger.