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Does the feed dog move as it should?
Are you sure the machine is not set on Winding Bobbin, or similar setting that would disable the needle and/or the feed dogs?
If the feed dogs themselves never go above the level of the top of the sewing machine's "table", then it won't propel the fabric along, of course.
There may be a problem with the mechanism that moves the feed dogs. How do they move, or not move, upon observation?