You can try the following methods to solve the problem of not connecting to WiFi.
First, make sure that the phone is close enough to the WiFi signal source and does not exceed the signal coverage range.
If none of this is a problem, you can try to disconnect the WiFi connection, forget about the WiFi and reconnect.
You can also try to turn on airplane mode, wait for a period of time to turn off airplane mode and try to connect to WiFi.
If the above methods do not solve the problem, you can try to update the phone system or set the WiFi sleep policy to \"never\" in the phone Settings, and sometimes will solve the connection problem.
You can't connect to the network because the router's wireless transmitter does not have open permission. So it won't matter if you're connected. You just have to ask them to turn on the wireless hotspot