Customer (name blocked for privacy),
The problem is do with your answering machine coming on/ and or the vibration setting.
Two things to try.
Firstly, you can remove the way the phone automatically goes to the answering machine, by chaning the relevant settings in the Phone Settings section.
Secondly, take the vibration setting off. There will be an option which has ring and vibration - take that off and it should work.
Hope that helps.