I have a single extension set up with 3CX Phone System, and have turned on the "enable voice mail" setting for it. The forwarding rules are set to redirect to "send call to my voice mail" when there is no answer. However, instead of allowing the caller to record voice mail, when the phone stops ringing it says "please enter extension number", followed by "please enter personal identification number". Is there anything I've missed? I'm sure voice mail was working when I first set it up, and I don't think I changed anything that might have broken it.