"No service" is displayed

 The network connection was lost. You may be in a weak reception area (in a
    tunnel or surrounded by buildings, for example). Move and try again.
 You are trying to access an option for which you have not taken out a
    subscription with your service provider. Contact the service provider for
    further details.

 

You have entered a number but it was not dialled

 Have you pressed the key?
 Are you accessing the right cellular network?
 You may have set an outgoing call barring option.

 

Your correspondent cannot reach you

 Is your phone switched on ( pressed for more than one second)?
 Are you accessing the right cellular network?
 You may have set an incoming call barring option.

 

Your correspondent cannot hear you speaking

 Have you switched off the microphone (Mute appears)?
 Are you holding the phone close enough to your mouth? The microphone is
    located in the bottom left of the phone.