Maybe it’s the light conditions you’re shooting in, maybe it’s you.

Your CPL filter should cut out the reflected light but remember that you need to rotate the outer element of your CPL filter to do so. To get the maximum polarisation from your CPL filter, use the 90 degree rule. To do this, make an L shape using your thumb and index finger. Point your thumb at the sun and wherever your index finger is pointed, that is the angle that will achieve maximum polarisation.