2:1 Diametric Projection in 2D

I’m trying to implement a 2D isometric game, well diametric with a 2:1 pixel ratio. Trouble is the rotation matrix I made doesn’t seem to work. It’s off by a little bit and doesn’t line up: enter image description here

I’m not sure if I did my rotation matrix correctly, here is a link to what I’m using. For the angles I used 45 degrees and arctan(1/2) which is roughly 26.5 degrees. I need all 3 axis, as I’m using lights and need the tiles to have depth.