Android - How to see mobile operator proxy settings

For GSM devices, as far as I know, the proxy settings for your mobile data connection are defined in the Access Point Name (APN). Go to Settings > Wireless and Networks > More > Mobile Networks > Access Point Names > [Your data APN] (your device's menu may differ slightly). Check the Proxy field - it's possible this got modified somehow. Might also be worth snooping around your carrier's website for the recommended APN settings and double-checking that everything is correct. Once finished, press [Menu] > Save and give it a test.

Did you switch from "Mobile data" to "WLAN" (also "Wifi" or "Wi-Fi" on SAMSUNG) last time for surfing in internet? If yes, then try this!

Sometimes when you enable "WLAN" before disabling "Mobile data" (top line, near the battery-charge-state or the current-date/time) the proxy settings for GSM will stay and be used for you WLAN!

All you need to do is:

  1. Disable "WLAN" (also "WiFi" or "Wi-Fi")!
  2. Enable "Mobile data"!
  3. Start Chrome and navigate to somewhere or search for something! Can you surf? If no, switching from "Mobile data" to "WLAN" was not the issue, else:
  4. Disable "Mobile data" and wait 2 seconds!
  5. Enable "WLAN"

It should work now.