One more thing that can cause setup headaches for iot devices using a mobile device, at least on Android, is a wifi setting. In the advanced wifi settings there is an option called “avoid bad connections”. If this is enabled, setting up your device can be troublesome. Initial setup sometimes involves your phone connecting directly to the device over WiFi. Your phone connects and then realizes there is no path to the internet and then disconnects again by switching to mobile data. The app then can’t finish its job talking to the device.
Make sure “avoid bad connections” option is disabled before setting up your iot (rachio) device. After you are done, you can choose to turn the option back on for normal phone use to avoid WiFi access points that don’t give you internet.