Simple and Easy are not mutually exclusive. When simplicity is maximized, easiness should be pretty high. However, it is possible that maximizing easiness can significantly reduce simplicity.

Also, Easy solutions appear easy, whereas simple solutions may or may not appear easy.

An easy solution is more likely to be a magical black box. A simple solution, if it is a black box, must not be magical but instead small and obvious in what it does.

Solve Problems Upstream is often an example of a simpler, but not always easy solution.