During the setup process, 2 things happen:
1. The Garage Door Controller will get your home wifi name and password.
2. The serial number of the GDC is saved in your app (iPhone or Android).
I believe, the first part was completed successfully, but the second part was not completed. I would suggest that you start from scratch again. Press the reset button of your GDC twice to factory-reset your GDC. Then in the app, select the setup process.