If you logout and then log back into your account, the app will force you through the setup process which can be confusing if you don't have new lights to set up. If you see this screen and you don't have any new lights to set up, hit the cancel button on the top left to go to "my lights".
If you click "OK, Let's do this", it won't see your existing devices, since they are already set up. The app will only looks for new devices which can cause confusion if you don't have any. It may look like the app can't see your existing devices.