Answering machine not working with voxalot?

[druids]

Hi,
please help me to set up properly my line to be able to use telephone answering machine: I have ata on dmz(pap2) and when I receive a call the phone is ringing and show me after a # of calls that the answering machine is on but the caller still hear the rings and never get the answering machine message and option to leave a message(on the caller side it still ringing even after the answer machine closed the connection). Please can any body help me? When I am using the ata and same phone connected directly to the provider(acanac) is working fine.