Hello. Please can someone help? This is our first 3CX installation and we're unable to receive incoming calls although we can make outgoing calls and internally everything works. We have an analogue phone line connected to a Grandstream GXW-4104 which is connected to our 3CX server on our LAN. The 3CX server is logging the following when the incoming call is made, but the call just rings and rings: 15:23:21.902 [CM302002]: Authentication failed due to unidentified source of: SipReq: INVITE email@example.com tid=ca967942ccb0a6f6 cseq=INVITE contact=192.168.3.253:5064 / 22683 from(wire) 15:23:21.793 [CM500002]: Unidentified incoming call. Review INVITE and adjust source identification: INVITE sip:firstname.lastname@example.org SIP/2.0 Via: SIP/2.0/UDP 192.168.3.253:5064;branch=z9hG4bKb504b8151fb61f06 Max-Forwards: 70 Contact: <sip:192.168.3.253:5064> To: <sip:email@example.com> From: "unknown"<sip:firstname.lastname@example.org>;tag=8aa69666dc63c121 Call-ID: email@example.com CSeq: 22682 INVITE Allow: INVITE, ACK, CANCEL, BYE, NOTIFY, REFER, OPTIONS, INFO, SUBSCRIBE, UPDATE, PRACK Supported: replaces, timer, path User-Agent: Grandstream GXW4104 (HW 1.1, Ch:0) 126.96.36.199 Content-Length: 0 15:23:21.793 [CM302001]: Authorization system can not identify source of: SipReq: INVITE firstname.lastname@example.org tid=b504b8151fb61f06 cseq=INVITE contact=192.168.3.253:5064 / 22682 from(wire) The "1000+" shown in the "To" field is set in the Unconditional Call Forward field on the Grandstream gateway as described in the configuration guide on the 3CX website. Any help would be much appreciated. Many thanks.