Motion tiles are white instead of black

I tried to do it traditionally by using a solid layer white a black color, turn off constrain proportions on Scale, bring it down to 80% and changing the blending mode to stencil alpha. Instead if it inverting the solid to make a letterbox, it disappear or turning white. I tried to do this even on the latest version of AE but the same thing happen i just want to fix that problem. I get there are alternatives to get a letterbox but i want to fix this problem

Or, make a black solid and draw a rectangular mask in the centre to reveal the underlying footage.

Or, download a free letterbox template file and simply drop it on top.  One example of such templates here:

352 Free Letterbox Templates for Video Editing (720 to 8K)

huskyan  wrote I was trying to make a letterbox with motion tile effect since using a solid layer with stencil alpha made it disappear.

That makes absolutely no sense.  If you want black letter boxing, make a black solid.  Duplicate it.  Move one up and one down. Boom.  Done.  Couldn't be easier.