When we tried to connect to the Wifi (ADSL) with WPA2 Security and TKIP encryption, after adding the password and trying to connect, Wifi gets connected, Wifi Symbol appears, and in a fraction of second it gets disconnected saying saved, secured with WPA2 under Wifi Settings.
As a first troubleshooting step we removed all the available Wifi Settings (long press on each of them + Forget) and tried to re-configuring but the same issue persisted.
We tried restarting the phone, changing Wifi router settings like removing WPA2 security, setting WPA security, changing TKIP to AES etc. but non worked.
We even tried connecting to some different Wifi router, but the same issue.
There was a Mcafee Security App installed on the phone that had Administrative rights, we deleted that app and tried connecting the wifi and it worked :)
Didn't find this solution anywhere on the internet, so before trying to factory reset your phone, just try removing or configuring anti-virus applications that may be causing this issue.