This is usually fixed by signing in again, even if the app isn’t asking you to:
- Select an Amazon delivery.
- On iOS, rest your finger on the “…” button until the menu appears. On Mac, hold the option (or alt) key on your keyboard and then click the “…” button.
- You should see a menu with some extra options—choose “Sign In”.
- Sign in there and press the “Done” button when you’re finished.