Can't paint on masking layer

[apheem]

I am currently following a tutorial and I follow every step and I have rewatched it but it doesn't make any sense. I have the layer selected and I pressed 'D' then 'X' to make sure black is selected and the hardness is 0% but for some reason no matter where I click it wont allow me to draw. But when I select the image it allows me to draw on the image. What is going wrong?

[Michael Bullo]

Change the blend mode of the brush from Overlay to Normal. This option is located in the options bar running across the top of Photoshop.

[Michael Bullo]

In reference to my previous post, you may have intentionally changed the brush blend mode at some point yourself. However, this option can also be changed by keyboard shortcuts.

Take this keyboard shortcut for example: Alt/Option + Shift + M

If you were using the Move tool and you had a layer selected, this keyboard shortcut would change the blending mode of that layer within the Layers panel to Multiply.

However, if you were using the Brush tool and triggered this keyboard shortcut then you would change the blending mode of the brush itself to Multiply.