DIAGNOSIS The setup process got stuck. The Air Pro creates its own temporary Wi-Fi network for initial setup, and if your phone switches networks or the process times out, it can get hung in this blinking state.
FIX You need to force a full reset of the Wi-Fi module. Unplug the purifier. Hold down the 'Fan Speed' button on the top panel and, while holding it, plug the power cord back in. Keep holding the button for about 10 seconds until you see all the lights flash. Release it. This performs a factory reset on the connectivity. Now, go through the app setup from scratch, making sure your phone is on your 2.4GHz Wi-Fi network (it doesn't support 5GHz for setup).
IF THAT DIDN'T WORK Some routers with certain security settings (like WPA3-only or specific firewall rules) can block the connection. As a test, try creating a simple, temporary 2.4GHz hotspot from another phone (with a simple password) and see if the Air Pro can connect to that. If it can, the issue is with your main router's configuration.
HEADS UP The unit needs a consistently strong 2.4GHz signal. If it's too far from your router or behind thick walls, it may connect but drop off frequently, causing the blinking light to return. Placement matters for connectivity, not just air flow.