There are a few reasons why this may happen.
- You might have applied too little of the RemovALL paint stripper. The paint absorbed it all and it stopped working. Remember that you should not be able to see your underlying paint after you have applied the paint remover.
- Your project was in the direct sun during a very warm day and the paint absorbed the stripper too quickly.
- Your project might have been painted with latex paint overtop of oil paint or vice versa, resulting in bad adhesion between the layers. In that case, the stripper will travel through the first layer or two then stop because it believes it has reached the surface.