Do you have the same thread in the bobbin as the needle?

Is the feed dog working? On my machines, smooth slick things don't get grabbed by the feed dogs,so the material just sits in the same place getting stitch after stitch is the same place. For instance, my boss wanted a button hole stitched onto card stock. It just doesn't work.

Try a strip of tissue paper at the seamline on top and bottom for less stickiness or smear a bit of baby powder on the plastic.

Try various tensions on the pressure foot (not the thread, the foot).

Try a 'roller foot" or a 'walking foot"

Did you get it resolved? It seems to me that the plastic in the material may be not letting the thread pass through easily.