There are a few troubleshooting checks I will need you to perform to see if they are successful in resolving the issue. Can you:
• Check the phone is seated in the base unit correctly & powered ON.
• Remove all other equipment connected to telephone sockets.
• Unplug the phone and check another phone directly into the main socket ensuring this is a VM socket and not one with a BT or Sky logo. If no alternative handset is available then ensure
the original phone is plugged into the main socket with no other pieces of equipment being plugged in.