The solution is as follows.
1. Router failure
Router failure is one of the most common reasons why phones can't connect to WiFi, and usually when this problem occurs, the router is usually stuck in a dead loop. At this time, we only need to unplug the router and restart the router to solve the problem, which can solve the problem that most mobile phones cannot connect to wifi. Or it is possible that the router has a hardware failure problem, at this time to send the router to repair.
Two, too many devices connected at the same time
This problem generally appears in some public places, such as some tea restaurants, work environments and other public places, it is likely that there are too many people connected to wifi, resulting in people unable to normally connect to the situation. In this case, you need to allocate the IP of each connected device of the router to avoid impact.
Three, beyond the range of signal coverage
The signal of the infinite network is easily affected by external interference, and the main problem is the distance problem. Generally, if the ordinary router is ten meters away from the connection signal, the signal will be very weak, or even unable to connect. So we'd better be as close to the router as possible when using it.
Four, mobile phone wireless card failure
Generally, mobile phones connect to wifi by relying on the wireless network card in the mobile phone, and sometimes the failure or aging of the wireless network card in the mobile phone is likely to cause the mobile phone to fail to connect to wifi normally. In this case, you can only take the phone to the repair center to repair.
To connect the mobile phone to wifi, you need to ensure that the password is correct. If the password is correct, you can reset the mobile phone network and then connect. Open the phone Settings, tap General, Transfer or Restore iPhone, select Restore, tap Restore Network Settings, tap Restore network Settings again, long press the power button and volume plus button, slide the slider to shut down, after shutdown, long press the power button to restart.