Guys, I have read here about people having this problem but I have not seen anyone say they have resolved the issue. Is there a fix. I can register an external line from the remote location and I can call all internal extensions and call external lines to 3CX from the external extension. The problem is that from within the internal extensions I cannot call the external extension. The line status shows the call trying to be made but the external extension dosen't even acknowledge that there's an incoming call - light stays green. I looked at the logs and I see where the 3cx server (192.168.19.102) is trying to contact the external client on 192.168.1.19 I kinda know that this is not going to work over the internet. Is there an issue with m configuration of external clients or is this an unfixed issue in the software. Please advise - oh by the way this is on version Version5.1.4393.0 18:41:46.656 Call::Terminate [CM503008]: Call(4): Call is terminated 18:41:20.168 MediaServerReporting::SetRemoteParty [MS210004] C:4.2:Offer provided. Connection(proxy mode): 126.96.36.199:9008(9009) 18:41:20.088 MediaServerReporting::SetRemoteParty [MS210000] C:4.1:Offer received. RTP connection: 192.168.19.25:49210(49211) 18:41:20.058 CallCtrl:nSelectRouteReq [CM503004]: Call(4): Calling: Ext:115@[Dev:sip:firstname.lastname@example.org:2051;line=7i9hf8ax] 18:41:20.048 CallCtrl:nSelectRouteReq [CM503010]: Making route(s) to [sip:email@example.com;user=phone] 18:41:20.048 CallLeg::setRemoteSdp Remote SDP is set for legC:4.1 18:41:20.048 Extension:rintEndpointInfo [CM505001]: Ext.100: Device info: Device Not Identified: User Agent not matched; Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [snom190/3.60x] Transport: [sip:192.168.19.102:5060] 18:41:20.008 CallCtrl:nIncomingCall [CM503001]: Call(4): Incoming call from Ext.100 to [sip:firstname.lastname@example.org;user=phone] 18:41:19.988 CallLeg:nNewCall [CM500002]: Info on incoming INVITE: INVITE sip:email@example.com;user=phone SIP/2.0 Via: SIP/2.0/UDP 192.168.19.25:2051;branch=z9hG4bK-ifjhdby4aaj3;rport=2051 Max-Forwards: 70 Contact: [sip:firstname.lastname@example.org:2051;line=tsjoxrbr] To: [sip:email@example.com;user=phone] From: "100"[sip:firstname.lastname@example.org];tag=gnwiah1nh1 Call-ID: 3c4380b3975e-1otecffesgre@snom190 CSeq: 2 INVITE Session-Expires: 3600 Accept: application/sdp Allow: INVITE, ACK, CANCEL, BYE, REFER, OPTIONS, NOTIFY, SUBSCRIBE, PRACK, MESSAGE, INFO Proxy-Authorization: Digest username="100",realm="3CXPhoneSystem",nonce="12860894479:d82aeb650cd7ce2efabfed0842847d49",uri="sip:email@example.com;user=phone",response="69b5f5ddccdc5859d34abd5aee7bfbc9",algorithm=md5 Supported: timer, 100rel, replaces User-Agent: snom190/3.60x Allow-Events: talk, hold, refer Content-Length: 0 P-Key-Flags: keys="