If you have two parallel planes with one density of 1 C/m^2 and the other with -1 C/m^2 density and you need to find the electric field at a point in the middle, how do you use Gauss's Law?

I drew a box enclosing one plane to find the electric field in the midpoint. I understand there's another plane exerting an additional force, but by Gauss's law it should only depend on the enclosed charge.

Is Gauss's Law being violated here?

If you have two parallel planes with one density of 1 C/m^2 and the other with -1 C/m^2 density and you need to find the electric field at a point in the middle, how do you use Gauss's Law?

I drew a box enclosing one plane to find the electric field in the midpoint. I understand there's another plane exerting an additional force, but by Gauss's law it should only depend on the enclosed charge.

Is Gauss's Law being violated here?