Generally toy machines have issues making a stitch. That is why many of us strongly suggest no one ever buy a toy to teach a child to sew. Rather start with a Singer 99 handcrank. I have a toy Necchi which I have set aside as it is so annoying. There are generally no possible adjustments to be made. In my case I fiddled with the needle and tension and finally got a length of stitching, but would never use it to try to make anything.
Are you using the correct 20x1 needle or did you use a 15x1 and pull it down before securing?