Why isn't the vertex color node working?

I’m simply trying to color over a texture. Ive worked with vertex colors many times.
The texture is multiplied by the vertex color and plugged into the bass color.

When I go to vertex paint no matter what I set any of the values or colors it wont paint.
Is there something that can cause you not to paint on a mesh?

no one has any idea what I could be doing wrong here???