There are two common possibilities for this problem, one is that there is a problem with the Settings of the wireless router, the type of encryption protocol that is opened can not be supported by your mobile phone, the most typical phenomenon of this situation is that the mobile phone can normally search for the network, and can normally connect to the network through password verification, but either can not get an IP address, or can not get an IP address after the Internet.
This can be adjusted on the wireless router by simply changing the previously specified protocol encryption mode to \"automatic\" and then restarting the wireless router once.
In addition, there is another possibility that the wireless router has the MAC address filtering function in the \"security\" function, resulting in devices with unbound MAC addresses that cannot access the Internet.
(Not if it's not turned on.)
Answer: This is your mobile phone 4g network signal disconnected. Because the local workers are repairing the 4g base station, so interrupted your mobile phone 4g network. You can wait a while, wait for them to fix it and then you can use it normally