The Activity app on my iPhone always shows the "setup" screen: "Set up Activity on your Apple Watch". I have already set up Activity on my Apple Watch; it works fine and shows the rings filling up each day. But I cannot access historical Activity data which should be displayed in the iPhone app.

I have tried restoring the watch from a backup and setting up the watch as new. Neither has worked.

A little background: I bought my Apple Watch along with my iPhone 6s+. That initial pairing worked without any bugs in Activity on phone or watch. However, two weeks after purchase, my iPhone experienced some kind of catastrophic failure. I got it replaced at the Apple Store. Since pairing my watch with the replacement phone, the iPhone Activity app has never recognized that I have already set up the Watch Activity app.