Who I have the same questioned this topic

I was told by someone trying to call me that they were not receiving my voicemail greeting.  The phone would ring, then when the voicemail was supposed to play it would just be silent.  I have checked both the iPhone (greeting/custom) and the message is recorded and I can hear it, but it will not play and no one can leave a message if I don't answer the call.  Dialing *86 and going into the greeting/voicemail menu also will allow me to hear my outgoing greeting message, and activate the greeting, but it still will not play when someone calls me and I don't answer the call.