This fault is related to the settings of the router. You need to check the settings of the router.
The reasons are as follows:
1. Currently, it does not support public network or enterprise network Wi-Fi hotspots and does not support WEP encryption;
2. It is recommended that you change the SSID to a combination of English and numbers;
3. Check if the password is entered correctly. You can reconnect the purifier by resetting it. You can try to delete the Wi-Fi password saved on your phone and re-enter the Wi-Fi password to confirm whether it is correct;
4. You need to turn off the router MAC address filtering, which usually prohibits any new devices from joining;
5. Do not turn on the hidden SSID function, which will make the device undetectable;
6. Turn on automatic IP address acquisition. Any new device needs to use this function to obtain an IP address;
7. Check whether the router is a public router, whether too many devices have been connected, and whether the number of connectable devices has reached the maximum value of the router.