It's been discovered that different ages of JuiceBoxes have the red/black pins in different positions (nearly 50/50%).

Using the same technique as removing the pilot wire in an earlier step, compare your new replacement relay and your original relay, and swap the red/black pins as needed.

The JuiceBox will work without doing this, but may report reverse energy. If you see erroneous energy reporting in the app (e.g. inverted power graphs, weird stats), flipping the red/black should fix it.