Hi @Susan, this answer may help you set up your device: Purple air sensor lost connection - #2 by Ethan_Breinholt.
You can try to disable mobile data on your device before connecting to the PurpleAir-**** network. Some phones will prioritize mobile data instead of using the PurpleAir-**** network as it does not provide an internet connection.
You can also try removing the SD card during the setup process.