quote Lori = Check to make sure you have the pressure on the foot adjusted. There is an adjustment for thread tension , and also an adjustment for the pressure on the foot. It may have gotten bumped or turned to low somehow. Double check all areas for lint , my first thought is you had a serious lint build up at the feed dogs.
and
quote Fluffygirl = Does your kenmore have a pressure setting above the presser bar (or inside the cover where the light is)? Could be a dial with numbers - usually 1-3. This controls the pressure pushing down on the fabric. When I accidentally changed mine to too light, the fabric wouldn't feed. Hope it is a simple fix.
I think this may be it... many newer machines have a little spring loaded ring around a post on top of the needle bar area. push down on the wheel (donut shaped around the post) and the post will shoot up...that is the lightest setting...as you push the post in the center downward, the foot pressure increases...look for the dial or the donut/post combo....