Why my solution for white/black dots and block puzzle doesn't work?

After what must have been at least one hour and a half, I finally thought I found the solution for the maze puzzle. However, the game wouldn't accept it. I found the right solution somewhere else on this website, but I'd like to know what's wrong with mine.

I don't think I mirrored any blocks, and I separated the white dots from the black ones.

Solution 1:

The top "L" block and the "I" block can't be rotated when solving the puzzle. You'll notice how the other two "L" blocks towards the bottom are slanted slightly, signifying that they can be rotated. You will need to keep the position of the first two mentioned blocks the same way they are shown in the puzzle, however you may rotate the other two blocks.