Hi, Background We've been setting up a new 3CX installation and for the best part it's been an easy, hastle free experience. We have a Patton 4114 4-port PSTN device, a gradwell VoIP trunk, 12 Snom extensions and they can all communicate in and out nicely on all routes... The problem We have one remote extension. It rings on an incoming call but we cannot answer the call. The phone model is a Snom 300 with latest firmware The 3CX server is a commercial (Small Business) Edition Outbound calls work fine with audio both ways working (RTP good) All port are forwarded correctly to the 3CX server at the head office (passes 3CX firewall check) We have followed the various 3CX how-tos and the settings seem to be correct http://www.3cx.com/blog/voip-howto/remote-extensions/ http://www.3cx.com/blog/docs/provisioni ... extension/ - UPDATED LINK Heres the verbose log during an incoming call: 14:27:56.473 [CM503008]: Call(3): Call is terminated 14:27:51.192 [CM503007]: Call(3): Device joined: sip:email@example.com:40600;rinstance=96514bfee704fc7e 14:27:51.192 [CM505001]: Ext.123: Device info: Device Identified: [Man: 3CX Ltd.;Mod: Voice Mail Menu;Rev: General] Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [3CX Voice Mail Menu] PBX contact: [sip:firstname.lastname@example.org:5060] 14:27:51.192 [CM503002]: Call(3): Alerting sip:email@example.com:40600;rinstance=96514bfee704fc7e 14:27:51.051 [CM503025]: Call(3): Calling Ext:Ext.123@[Dev:sip:firstname.lastname@example.org:40600;rinstance=96514bfee704fc7e] 14:27:50.989 [CM503005]: Call(3): Forwarding: Ext:Ext.123@[Dev:sip:email@example.com:40600;rinstance=96514bfee704fc7e] 14:27:50.989 [CM503003]: Call(3): Call to sip:firstname.lastname@example.org:5060 has failed; Cause: 408 Request Timeout; internal 14:27:36.177 Currently active calls - 1:  14:27:18.942 [CM503025]: Call(3): Calling Ext:Ext.230@[Dev:sip:email@example.com:2051;line=1x1dbl4f] 14:27:18.755 [CM503004]: Call(3): Route 1: Ext:Ext.230@[Dev:sip:firstname.lastname@example.org:2051;line=1x1dbl4f] 14:27:18.755 [CM503010]: Making route(s) to <sip:email@example.com:5060> 14:27:09.864 [CM503007]: Call(3): Device joined: sip:firstname.lastname@example.org:40600;rinstance=e134a1dc9a4d2db9 14:27:09.849 [CM503007]: Call(3): Device joined: sip:email@example.com:5064 Where xx.xx.xx.xx is the public IP of the 3CX server and yy.yy.yy.yy is the public IP at the remote site. Any help would be greatly appreciated!