We have a 2nd NexVortex DID hitting our 3cx version 5 box. This number is for faxes only. 3cx sees the incoming call and directs to the 888 fax box. That's about it. It disconnects with the following error: [CM503003]: Call(116): Call to sip:firstname.lastname@example.org:5060 has failed; Cause: 404 Requested user not found; from IP:192.168.7.8 This was preceded by audio codec negotiation issues. Any advice would be very appreciated. Thanks and hope your New Year has started off well.