The reasons and solutions for wifi connection are as follows;
1. The wifi password is wrong, so it cannot be connected. [Enter the correct password].
2. The network Settings of the mobile phone are faulty [Restore the default network Settings and then connect].
3. The wifi connection is not able to access the Internet because the wifi has no network signal or the network cable is pulled out [just plug in the network cable].
4. Mobile phone hardware failure leads to Internet access [Go to the mobile phone store or after-sales inspection and maintenance can be].