Nokia Lumia 800 - I cannot connect to the internet using a mobile data connection on my Lumia (Windows Phone 7)

1. Restart your phone with SIM card inserted. Press and hold the Power and Volume down keys simultaneously until the phone vibrates. Release and the phone will restart.

2. Enable the cellular data connection on your phone. Go to Settings > mobile network (cellular) and switch Data connection to On.

3. Check that your data roaming is activated when you are not in your home network. Go to Settings > mobile network (cellular) and select Data roaming options.

4. If above steps do not help, try to configure the internet settings manually.

  1. Download and install Network Setup application from Store (Marketplace).
  2. Start the app, and tap +.
  3. You must enter Connection name and Access Point Name (Internet APN). The other settings are optional and depend on your mobile operator. Confirm the settings with your network operator.
  4. Select Make this my current APN and tap Save.