Drony helps apps like Play Store and Whatsapp connect to the Internet when you use a proxy server which needs Authentication.
Download it from Google Play Store ( https://play.google.com/store/apps/details?id=org.sandroproxy.drony&hl=en ).
Now go to Wifi settings and hold the Wifi network which you intend to use. Click ‘Modify Network’. Check ‘Advanced Options’. Choose ‘Manual’ in proxy settings. Type ‘localhost’ in Proxy Hostname and put the port as 8020.
Now start Drony. Swipe left to goto Settings. Choose Wifi under Network. There you will see your Wifi network. Click on it. Set proxy type as ‘Manual’ . Move down and set the other Proxy type as ‘Plain’. Put your hostname, port, username and password. Put any Domain name.
Now go back to the home screen and Click on ‘Off’ to set it as ‘On’. Your apps will now route through the proxy automatically.