Singer zigzag 457 Stylist not threading bobbin/making stitch?

Singer Model 457 zigzag Stylist will not thread bobbin. The gears on the long bar on the top both turn; the gears on the long bar underneath both turn. The timing has been reset. What can it be preventing the bobbin thread from being taken through the needle plate and make stitches? Please send a noted photo so I am telling you correctly the gears are working.
Marcia, October 2022


done
How do we know where to send a photo?

Ffghh, October 2022
link Click here to see other fixes for Singer.