Symbols not creating

I made a successful symbol of a dogs from right leg. Then I tried to do it for the rest of the appendages and when I hit the create symbol button it would creat a symbol with nothing in it. I did this multiple times with different layers and it always came out with nothing in the symbol library. It would creat a symbol file but nothing would be in it. Any ideas?

Even when I use the edit tab> then the Creat Symbol button is greyed out

Are you creating symbols from the Camera View? Is the drawing that you’re clicking on visible (the checkbox checked on) and selected in the Timeline?