First of all, make sure that your landline is set up correctly and plugged in securely. If you have DSL High Speed Internet, you will need a DSL filter (Not included with product).
Second, If that is all fine, check that the phone is powered on and not dead. Make sure the battery is inserted the correct way.
Third, try resetting the phone by unplugging all cables and batteries for 1 minute, then plug it all back in.
If none of the above work, you may have a faulty phone, and it will need replacement, as there is no other way to fix this. Hope this helps!