I just got my Hub and button combo and started following the setup process. Plugged up the Hub to get a solid red light. Went to add a Hub in the app, it found my serial number, tapped it, and now the progress bar is stuck about 33% around and it says "Looking for Hub".
I've killed the app and relaunched and did a hard reset with the tiny button the Hub and it still does the same thing.
Update: Looks like the button that was included in my package doesn't work either. No light appears when I hold the button and I opened it to make sure the battery was facing the proper direction.