Hoi Nandan Raj,
A late response here, but your issue could have used some more information.
Unfortunately, BlackBerry has since ended support for all mobile devices and has shutdown all servers related to those devices, including the BlackBerry Classic.
If your issue, was trying to set-up your BlackBerry Classic and are not able to pass the Wi-Fi screen, this is due to the server shutdown and your device will not be able to properly set-up due to that.
[link|https://www.blackberry.com/us/en/support/devices/end-of-life|BlackBerry: End-of-Life Announcement|new_window=true]
Not the news to hear about a device you use, but hopefully this helps with your issue.