I have two 3cx systems we recently noticed that we have several fax DID's and on both systems one or two of them do not work. I get an error from the carrier side basically the line is not answering. If i flip it to an extension and dial it right back it works and the phone rings. On both systems I have multiple inbound fax DID's and some of them work and some have this issue. It was all working when we setup and installed in the last few months. All 15.5 and latest updates. Anyone have any idea? Ive gone back and forth on checking all the settings, I mean there isnt much obviously.