i found the solution, in the fragment shader in de shadow function:

if(fSub<vShadowSmooth.z){
          visibility -= 0.1*(1.0-fSub);
            
          }

I found the solution: in the fragment shader in the shadow function it should be:

if(fSub<vShadowSmooth.z){
          visibility -= 0.1*(1.0-fSub);
            
          }