(Connection was established but it gives me a wrong feedback. )
I'm not sure what this means, but it could be that you're using the wrong password encryption. Is this a public wifi signal you're trying to connect to?
If so, try deleting the saved password from Keychain.app (search in Keychain for the Wifi name), then try connecting to the wifi again. When it asks for the password, try changing the encryption code from WPA/WPA2 to WEP and see if it will accept the password.
Thanks a lot.
I mean when I enter the RIGHT password to my own Wi-Fi and the network can be set correctly and I can browse web pages but the notification was that the connection failed.
I deleted the password from Keychain.app but the problem is still there and I don't know what to do next.
Do I need to restore the system?