During IR Setup, if you are using a Sensor Puck to pair with your IR Device, it will temporarily connect to your home WiFi to download the IR codes. Try moving your Sensor Puck in better range of your home WiFi.
It's possible the IR download may have been interrupted, or not completed. You can force Flair to re-download your IR codes:
- In the Flair app, go to Home Settings → IR Devices
- Expand the IR Device you are setting up
- Tap "Redownload IR Codes"