Trying to make background transparent on my vector image, not working for inside of lines.

After turning on transparency, image tracing, and expanding the image I can delete the background but can't make it transparent on the inside of lines instead, the path fills black (photos below).

My main goal is to have this vector image have a transparent background for everything except the black lines.

Any help is appreciated, thanks.

The third photo is after I hit delete on the path.