Usually, with this issue, if you just redo the setup again, it should fix the issue. However, should it not, the following steps will resolve the problem;
Download the latest Grainfather app
Clear the credentials on the controller
Restart the controller
Retry the setup
If that fails, try connecting the controller to a different internet connection (like a second phone's hotspot). It could be an issue with your home network not allowing a new device to communicate to our servers. If the second phone hotspot is successful, you should be able to do the setup again and assign it to your home network.