First, the failing case: [Mar 16 14:54:02] VERBOSE[24520] logger.c: Asterisk Queue Logger restarted [Mar 16 14:54:17] VERBOSE[22320] pbx_variables.c: Setting global variable 'SIPDOMAIN' to '192.168.8.18' [Mar 16 14:54:17] VERBOSE[26155][C-00000037] pbx.c: Executing [telekomSipNumber9@ankommend:1] NoOp("PJSIP/telekomSipNumber5-00000067", "") in new stack [Mar 16 14:54:17] VERBOSE[26155][C-00000037] pbx.c: Executing [telekomSipNumber9@ankommend:2] ExecIf("PJSIP/telekomSipNumber5-00000067", "1?Set(CALLERID(num)=0171123456789)") in new stack [Mar 16 14:54:17] VERBOSE[26155][C-00000037] pbx.c: Executing [telekomSipNumber9@ankommend:3] AGI("PJSIP/telekomSipNumber5-00000067", "ldaplookup.agi") in new stack [Mar 16 14:54:17] VERBOSE[26155][C-00000037] res_agi.c: Launched AGI Script /var/lib/asterisk/agi-bin/ldaplookup.agi [Mar 16 14:54:17] VERBOSE[26155][C-00000037] res_agi.c: AGI Script ldaplookup.agi completed, returning 0 [Mar 16 14:54:17] VERBOSE[26155][C-00000037] pbx.c: Executing [telekomSipNumber9@ankommend:4] ExecIf("PJSIP/telekomSipNumber5-00000067", "0?Set(CALLERID(name)=0171123456789)") in new stack [Mar 16 14:54:17] VERBOSE[26155][C-00000037] pbx.c: Executing [telekomSipNumber9@ankommend:5] Verbose("PJSIP/telekomSipNumber5-00000067", "myself") in new stack [Mar 16 14:54:17] VERBOSE[26155][C-00000037] app_verbose.c: myself [Mar 16 14:54:17] VERBOSE[26155][C-00000037] pbx.c: Executing [telekomSipNumber9@ankommend:6] ExecIf("PJSIP/telekomSipNumber5-00000067", "1?Set(CALLERID(name)=myself@Bo)") in new stack [Mar 16 14:54:17] VERBOSE[26155][C-00000037] pbx.c: Executing [telekomSipNumber9@ankommend:7] GotoIf("PJSIP/telekomSipNumber5-00000067", "0?nacht:tag") in new stack [Mar 16 14:54:17] VERBOSE[26155][C-00000037] pbx_builtins.c: Goto (ankommend,telekomSipNumber9,11) [Mar 16 14:54:17] VERBOSE[26155][C-00000037] pbx.c: Executing [telekomSipNumber9@ankommend:11] Dial("PJSIP/telekomSipNumber5-00000067", "PJSIP/myDeskPhone&PJSIP/myDectClient,30") in new stack [Mar 16 14:54:17] VERBOSE[26155][C-00000037] app_dial.c: Called PJSIP/myDeskPhone [Mar 16 14:54:17] VERBOSE[26155][C-00000037] app_dial.c: Called PJSIP/myDectClient [Mar 16 14:54:17] VERBOSE[26155][C-00000037] app_dial.c: PJSIP/myDectClient-00000069 connected line has changed. Saving it until answer for PJSIP/telekomSipNumber5-00000067 [Mar 16 14:54:17] VERBOSE[26155][C-00000037] app_dial.c: PJSIP/myDeskPhone-00000068 connected line has changed. Saving it until answer for PJSIP/telekomSipNumber5-00000067 [Mar 16 14:54:17] VERBOSE[26155][C-00000037] app_dial.c: Now forwarding PJSIP/telekomSipNumber5-00000067 to 'Local/000forwardTargetFailing@abgehend' (thanks to PJSIP/myDeskPhone-00000068) [Mar 16 14:54:17] VERBOSE[26155][C-00000037] app_dial.c: Not accepting call completion offers from call-forward recipient Local/000forwardTargetFailing@abgehend-00000018;1 [Mar 16 14:54:17] VERBOSE[26232][C-00000037] pbx.c: Executing [000forwardTargetFailing@abgehend:1] NoOp("Local/000forwardTargetFailing@abgehend-00000018;2", "") in new stack [Mar 16 14:54:17] ERROR[26232][C-00000037] res_pjsip_header_funcs.c: This function requires a PJSIP channel. [Mar 16 14:54:17] VERBOSE[26232][C-00000037] pbx.c: Executing [000forwardTargetFailing@abgehend:2] ExecIf("Local/000forwardTargetFailing@abgehend-00000018;2", "0?Dial(PJSIP/000forwardTargetFailing@telekomSipNumber9,,b(clirhandler^addheader^1)):Dial(PJSIP/000forwardTargetFailing@telekomSipNumber9") in new stack [Mar 16 14:54:17] VERBOSE[26232][C-00000037] app_dial.c: Called PJSIP/000forwardTargetFailing@telekomSipNumber9 [Mar 16 14:54:17] VERBOSE[26155][C-00000037] app_dial.c: Local/000forwardTargetFailing@abgehend-00000018;1 connected line has changed. Saving it until answer for PJSIP/telekomSipNumber5-00000067 [Mar 16 14:54:18] VERBOSE[26232][C-00000037] app_dial.c: PJSIP/telekomSipNumber9-0000006a is ringing [Mar 16 14:54:18] VERBOSE[26155][C-00000037] app_dial.c: Local/000forwardTargetFailing@abgehend-00000018;1 is ringing [Mar 16 14:54:18] VERBOSE[26232][C-00000037] app_dial.c: PJSIP/telekomSipNumber9-0000006a is ringing [Mar 16 14:54:18] VERBOSE[26232][C-00000037] app_dial.c: PJSIP/telekomSipNumber9-0000006a answered Local/000forwardTargetFailing@abgehend-00000018;2 [Mar 16 14:54:18] VERBOSE[20944] res_rtp_asterisk.c: 0x742238f8 -- Strict RTP learning after remote address set to: 217.0.6.52:36938 [Mar 16 14:54:18] VERBOSE[26234][C-00000037] bridge_channel.c: Channel PJSIP/telekomSipNumber9-0000006a joined 'simple_bridge' basic-bridge [Mar 16 14:54:18] VERBOSE[26155][C-00000037] app_dial.c: Local/000forwardTargetFailing@abgehend-00000018;1 answered PJSIP/telekomSipNumber5-00000067 [Mar 16 14:54:18] VERBOSE[26232][C-00000037] bridge_channel.c: Channel Local/000forwardTargetFailing@abgehend-00000018;2 joined 'simple_bridge' basic-bridge [Mar 16 14:54:18] VERBOSE[20944] res_rtp_asterisk.c: 0x73c1fea8 -- Strict RTP learning after remote address set to: 217.0.6.52:61248 [Mar 16 14:54:18] VERBOSE[26235][C-00000037] bridge_channel.c: Channel Local/000forwardTargetFailing@abgehend-00000018;1 joined 'simple_bridge' basic-bridge <9d8c8380-3379-46a0-83c4-1c3edfe395d3> [Mar 16 14:54:18] VERBOSE[26155][C-00000037] bridge_channel.c: Channel PJSIP/telekomSipNumber5-00000067 joined 'simple_bridge' basic-bridge <9d8c8380-3379-46a0-83c4-1c3edfe395d3> [Mar 16 14:54:30] VERBOSE[26155][C-00000037] bridge_channel.c: Channel PJSIP/telekomSipNumber5-00000067 left 'simple_bridge' basic-bridge <9d8c8380-3379-46a0-83c4-1c3edfe395d3> [Mar 16 14:54:30] VERBOSE[26235][C-00000037] bridge_channel.c: Channel Local/000forwardTargetFailing@abgehend-00000018;1 left 'simple_bridge' basic-bridge <9d8c8380-3379-46a0-83c4-1c3edfe395d3> [Mar 16 14:54:30] VERBOSE[26155][C-00000037] pbx.c: Spawn extension (ankommend, telekomSipNumber9, 11) exited non-zero on 'PJSIP/telekomSipNumber5-00000067' [Mar 16 14:54:30] VERBOSE[26155][C-00000037] pbx.c: Executing [h@ankommend:1] GotoIf("PJSIP/telekomSipNumber5-00000067", "1?done") in new stack [Mar 16 14:54:30] VERBOSE[26155][C-00000037] pbx_builtins.c: Goto (ankommend,h,3) [Mar 16 14:54:30] VERBOSE[26155][C-00000037] pbx.c: Executing [h@ankommend:3] NoOp("PJSIP/telekomSipNumber5-00000067", "") in new stack [Mar 16 14:54:30] VERBOSE[26232][C-00000037] bridge_channel.c: Channel Local/000forwardTargetFailing@abgehend-00000018;2 left 'simple_bridge' basic-bridge [Mar 16 14:54:30] VERBOSE[26234][C-00000037] bridge_channel.c: Channel PJSIP/telekomSipNumber9-0000006a left 'simple_bridge' basic-bridge [Mar 16 14:54:30] VERBOSE[26232][C-00000037] pbx.c: Spawn extension (abgehend, 000forwardTargetFailing, 2) exited non-zero on 'Local/000forwardTargetFailing@abgehend-00000018;2' Now, the working case: [Mar 16 14:57:20] VERBOSE[22320] pbx_variables.c: Setting global variable 'SIPDOMAIN' to '192.168.8.18' [Mar 16 14:57:20] VERBOSE[26259][C-00000038] pbx.c: Executing [telekomSipNumber9@ankommend:1] NoOp("PJSIP/telekomSipNumber5-0000006b", "") in new stack [Mar 16 14:57:20] VERBOSE[26259][C-00000038] pbx.c: Executing [telekomSipNumber9@ankommend:2] ExecIf("PJSIP/telekomSipNumber5-0000006b", "1?Set(CALLERID(num)=0171123456789)") in new stack [Mar 16 14:57:20] VERBOSE[26259][C-00000038] pbx.c: Executing [telekomSipNumber9@ankommend:3] AGI("PJSIP/telekomSipNumber5-0000006b", "ldaplookup.agi") in new stack [Mar 16 14:57:20] VERBOSE[26259][C-00000038] res_agi.c: Launched AGI Script /var/lib/asterisk/agi-bin/ldaplookup.agi [Mar 16 14:57:20] VERBOSE[26259][C-00000038] res_agi.c: AGI Script ldaplookup.agi completed, returning 0 [Mar 16 14:57:20] VERBOSE[26259][C-00000038] pbx.c: Executing [telekomSipNumber9@ankommend:4] ExecIf("PJSIP/telekomSipNumber5-0000006b", "0?Set(CALLERID(name)=0171123456789)") in new stack [Mar 16 14:57:20] VERBOSE[26259][C-00000038] pbx.c: Executing [telekomSipNumber9@ankommend:5] Verbose("PJSIP/telekomSipNumber5-0000006b", "myself") in new stack [Mar 16 14:57:20] VERBOSE[26259][C-00000038] app_verbose.c: myself [Mar 16 14:57:20] VERBOSE[26259][C-00000038] pbx.c: Executing [telekomSipNumber9@ankommend:6] ExecIf("PJSIP/telekomSipNumber5-0000006b", "1?Set(CALLERID(name)=myself@Bo)") in new stack [Mar 16 14:57:20] VERBOSE[26259][C-00000038] pbx.c: Executing [telekomSipNumber9@ankommend:7] GotoIf("PJSIP/telekomSipNumber5-0000006b", "0?nacht:tag") in new stack [Mar 16 14:57:20] VERBOSE[26259][C-00000038] pbx_builtins.c: Goto (ankommend,telekomSipNumber9,11) [Mar 16 14:57:20] VERBOSE[26259][C-00000038] pbx.c: Executing [telekomSipNumber9@ankommend:11] Dial("PJSIP/telekomSipNumber5-0000006b", "PJSIP/myDeskPhone&PJSIP/myDectClient,30") in new stack [Mar 16 14:57:20] VERBOSE[26259][C-00000038] app_dial.c: Called PJSIP/myDeskPhone [Mar 16 14:57:20] VERBOSE[26259][C-00000038] app_dial.c: Called PJSIP/myDectClient [Mar 16 14:57:20] VERBOSE[26259][C-00000038] app_dial.c: PJSIP/myDectClient-0000006d connected line has changed. Saving it until answer for PJSIP/telekomSipNumber5-0000006b [Mar 16 14:57:20] VERBOSE[26259][C-00000038] app_dial.c: PJSIP/myDeskPhone-0000006c connected line has changed. Saving it until answer for PJSIP/telekomSipNumber5-0000006b [Mar 16 14:57:20] VERBOSE[26259][C-00000038] app_dial.c: Now forwarding PJSIP/telekomSipNumber5-0000006b to 'Local/000forwardTargetWorking@abgehend' (thanks to PJSIP/myDeskPhone-0000006c) [Mar 16 14:57:20] VERBOSE[26259][C-00000038] app_dial.c: Not accepting call completion offers from call-forward recipient Local/000forwardTargetWorking@abgehend-00000019;1 [Mar 16 14:57:20] VERBOSE[26336][C-00000038] pbx.c: Executing [000forwardTargetWorking@abgehend:1] NoOp("Local/000forwardTargetWorking@abgehend-00000019;2", "") in new stack [Mar 16 14:57:20] ERROR[26336][C-00000038] res_pjsip_header_funcs.c: This function requires a PJSIP channel. [Mar 16 14:57:20] VERBOSE[26336][C-00000038] pbx.c: Executing [000forwardTargetWorking@abgehend:2] ExecIf("Local/000forwardTargetWorking@abgehend-00000019;2", "0?Dial(PJSIP/000forwardTargetWorking@telekomSipNumber9,,b(clirhandler^addheader^1)):Dial(PJSIP/000forwardTargetWorking@telekomSipNumber9") in new stack [Mar 16 14:57:20] VERBOSE[26336][C-00000038] app_dial.c: Called PJSIP/000forwardTargetWorking@telekomSipNumber9 [Mar 16 14:57:20] VERBOSE[26259][C-00000038] app_dial.c: Local/000forwardTargetWorking@abgehend-00000019;1 connected line has changed. Saving it until answer for PJSIP/telekomSipNumber5-0000006b [Mar 16 14:57:21] VERBOSE[26336][C-00000038] app_dial.c: PJSIP/telekomSipNumber9-0000006e is making progress passing it to Local/000forwardTargetWorking@abgehend-00000019;2 [Mar 16 14:57:21] VERBOSE[26259][C-00000038] app_dial.c: Local/000forwardTargetWorking@abgehend-00000019;1 is making progress passing it to PJSIP/telekomSipNumber5-0000006b [Mar 16 14:57:21] VERBOSE[24039] res_rtp_asterisk.c: 0x73c16d68 -- Strict RTP learning after remote address set to: 217.0.6.52:65130 [Mar 16 14:57:21] VERBOSE[26336][C-00000038] app_dial.c: PJSIP/telekomSipNumber9-0000006e is making progress passing it to Local/000forwardTargetWorking@abgehend-00000019;2 [Mar 16 14:57:21] VERBOSE[26259][C-00000038] app_dial.c: Local/000forwardTargetWorking@abgehend-00000019;1 is making progress passing it to PJSIP/telekomSipNumber5-0000006b [Mar 16 14:57:22] VERBOSE[26259][C-00000038] app_dial.c: PJSIP/myDectClient-0000006d is ringing [Mar 16 14:57:22] VERBOSE[26259][C-00000038] app_dial.c: PJSIP/myDectClient-0000006d is ringing [Mar 16 14:57:27] VERBOSE[20944] res_rtp_asterisk.c: 0x73c1fea8 -- Strict RTP learning after remote address set to: 217.0.6.52:46184 [Mar 16 14:57:27] VERBOSE[26336][C-00000038] app_dial.c: PJSIP/telekomSipNumber9-0000006e answered Local/000forwardTargetWorking@abgehend-00000019;2 [Mar 16 14:57:27] VERBOSE[26259][C-00000038] app_dial.c: Local/000forwardTargetWorking@abgehend-00000019;1 answered PJSIP/telekomSipNumber5-0000006b [Mar 16 14:57:27] VERBOSE[26340][C-00000038] bridge_channel.c: Channel PJSIP/telekomSipNumber9-0000006e joined 'simple_bridge' basic-bridge <401e54ea-8b43-4bc9-91da-774545ccb870> [Mar 16 14:57:27] VERBOSE[26336][C-00000038] bridge_channel.c: Channel Local/000forwardTargetWorking@abgehend-00000019;2 joined 'simple_bridge' basic-bridge <401e54ea-8b43-4bc9-91da-774545ccb870> [Mar 16 14:57:27] VERBOSE[26341][C-00000038] bridge_channel.c: Channel Local/000forwardTargetWorking@abgehend-00000019;1 joined 'simple_bridge' basic-bridge <0e2bbdc6-ea71-47b0-87cc-82d5c85ab37f> [Mar 16 14:57:27] VERBOSE[26259][C-00000038] bridge_channel.c: Channel PJSIP/telekomSipNumber5-0000006b joined 'simple_bridge' basic-bridge <0e2bbdc6-ea71-47b0-87cc-82d5c85ab37f> [Mar 16 14:57:27] VERBOSE[26259][C-00000038] res_rtp_asterisk.c: 0x73c16d68 -- Strict RTP switching to RTP target address 217.0.6.52:65130 as source [Mar 16 14:57:27] VERBOSE[26341][C-00000038] bridge.c: Move-swap optimizing Local/000forwardTargetWorking@abgehend-00000019;2 <-- PJSIP/telekomSipNumber5-0000006b. [Mar 16 14:57:27] VERBOSE[26341][C-00000038] bridge_channel.c: Channel PJSIP/telekomSipNumber5-0000006b left 'simple_bridge' basic-bridge <0e2bbdc6-ea71-47b0-87cc-82d5c85ab37f> [Mar 16 14:57:27] VERBOSE[26341][C-00000038] bridge_channel.c: Channel Local/000forwardTargetWorking@abgehend-00000019;2 left 'simple_bridge' basic-bridge <401e54ea-8b43-4bc9-91da-774545ccb870> [Mar 16 14:57:27] VERBOSE[26341][C-00000038] bridge_channel.c: Channel PJSIP/telekomSipNumber5-0000006b swapped with Local/000forwardTargetWorking@abgehend-00000019;2 into 'simple_bridge' basic-bridge <401e54ea-8b43-4bc9-91da-774545ccb870> [Mar 16 14:57:27] VERBOSE[26341][C-00000038] bridge_channel.c: Channel Local/000forwardTargetWorking@abgehend-00000019;1 left 'simple_bridge' basic-bridge <0e2bbdc6-ea71-47b0-87cc-82d5c85ab37f> [Mar 16 14:57:27] VERBOSE[26336][C-00000038] pbx.c: Spawn extension (abgehend, 000forwardTargetWorking, 2) exited non-zero on 'Local/000forwardTargetWorking@abgehend-00000019;2' [Mar 16 14:57:27] VERBOSE[26259][C-00000038] res_rtp_asterisk.c: 0x73c16d68 -- Strict RTP learning complete - Locking on source address 217.0.6.52:65130 [Mar 16 14:57:27] VERBOSE[26340][C-00000038] res_rtp_asterisk.c: 0x73c1fea8 -- Strict RTP switching to RTP target address 217.0.6.52:46184 as source [Mar 16 14:57:29] VERBOSE[26259][C-00000038] bridge_channel.c: Channel PJSIP/telekomSipNumber5-0000006b left 'simple_bridge' basic-bridge <401e54ea-8b43-4bc9-91da-774545ccb870> [Mar 16 14:57:29] VERBOSE[26340][C-00000038] bridge_channel.c: Channel PJSIP/telekomSipNumber9-0000006e left 'simple_bridge' basic-bridge <401e54ea-8b43-4bc9-91da-774545ccb870> [Mar 16 14:57:29] VERBOSE[26259][C-00000038] pbx.c: Spawn extension (ankommend, telekomSipNumber9, 11) exited non-zero on 'PJSIP/telekomSipNumber5-0000006b' [Mar 16 14:57:29] VERBOSE[26259][C-00000038] pbx.c: Executing [h@ankommend:1] GotoIf("PJSIP/telekomSipNumber5-0000006b", "1?done") in new stack [Mar 16 14:57:29] VERBOSE[26259][C-00000038] pbx_builtins.c: Goto (ankommend,h,3) [Mar 16 14:57:29] VERBOSE[26259][C-00000038] pbx.c: Executing [h@ankommend:3] NoOp("PJSIP/telekomSipNumber5-0000006b", "") in new stack