1) Whether the WiFi network is normal (you can connect WiFi with your mobile phone to test);
2) Whether the device has entered the connected state(the indicator light flashes red quickly);
3) Is the WiFi password entered correctly?
4) The distance between the device, router, and mobile phone is closer (the test is recommended to be in the range of 1-2 meters)
5) Confirm the router configuration
a. 5G WiFi is not supported; dual-band routers need to close the 5G frequency band);
b. Routers that do not support connection to enterprise-level security protocols;
c. WiFi launched by modems (commonly known as cats)is not supported;
d. Close AP isolation;
e. Does not support network bridging!
f. Whether WiFi has been hidden?
g. The frequency band bandwidth is changed to 20MHz;
h. Router restart
After confirming the above information, restore the router and device to pair again.