Please post the name of the program you use so a Moderator may move this message
-A program would be Photoshop or Dreamweaver or Muse or Premiere Pro or ???
I think it's Photoshop. So I move it in the appropriate forum.
Do you have used any plugin?
Hello, When the brush tool does not work, check
1) that you are trying to paint on the correct layer, on all channels, and not on a mask
2) that the brush opacity is not close to zero
3) that the brush blending mode is on Normal, or would work with the selected color
4) that there is not a selection somewhere else (CTRL+D) (or that a layer mask hides the area you are trying to paint on)
5) that there is not a layer on top that hides your painting.
6) that the layer you are painting on does not have a blending mode that would hide the color you apply, or its opacity is not too low
I might forget something, but you have several starting points!