[SOLVED] Mac Self Assigned IP Address issue with wifi

The other day I was facing this problem while connecting to the new internet connection in my office. after searching on the interned it took me a while to fix
The solution I am going to present is same as pulling the plug but it worked for me.

So this solution worked in the below scenario for me where the router IP is not present.
click on the wifi icon => select open network preferences => click advanced => select TCP/IP

Now if you have this scenario simply follow the below steps

-- Open the finder
-- click file => Go
-- Enter '/Library/Preferences/SystemConfiguration'

-- And delete the below files (Dont worry the OS will regenerate these files but to be on safe side just move them to trash)
com.apple.airport.preferences.plist
com.apple.network.eapolclient.configuration.plist
NetworkInterfaces.plist
preferences.plist
-- Restart your computer
This worked for me. let me know if it doesn't work for you.