What can I do if I cannot send messages, phone not working, no mobile data connection on my Nokia Lumia with Windows Phone 8

If your network service provider supports 4G/LTE (Long-Term Evolution) for smartphones, you can enjoy the benefits of higher data speeds with your Nokia Lumia 820, Lumia 920 or Lumia 822. However, 4G/LTE might not be supported by your network service provider or by the service provider you are using when traveling. In these cases, you may not be able to make or receive calls, send or receive messages or use mobile data connections.

To make sure your phone works seamlessly when full 4G/LTE service is not available, it is recommended that you change the highest connection speed from 4G to 3G.

To do this,

  1. Go to Settings.
  2. Tap mobile network (or cellular).
  3. Tap Highest connection speed and select 2G.
  4. Wait for at least 5 seconds and select 3G.

For more information, contact your network service provider.