DIAGNOSIS The machine is failing to join your wireless network during the app setup process.
FIX This is a multi-cause problem. Follow this checklist. 1. Ensure your phone's Bluetooth is on and you are using the Dyson Link app. 2. Your WiFi network must be a 2.4GHz band. The BP04 does not connect to 5GHz networks. 3. Temporarily disable your mobile data during setup to force the app through WiFi. 4. Move the purifier and your phone closer to the router. 5. Perform a hard reset on the purifier by holding the power button on the machine for 10 seconds until it restarts, then retry.
IF THAT DIDN'T WORK Some network security settings block the connection. Try creating a guest network on your router (2.4GHz) with a simpler password (letters and numbers only) and connect the Dyson to that network first.
HEADS UP The initial setup requires both Bluetooth (for pairing phone to machine) and WiFi. The machine cannot connect to enterprise networks with splash pages (like universities or some apartments).