Here's the SIP trace. The only thing that catches my eye is the 503 Service Unavailable...


freeswitch@heg_sip> /exit
root@heg_sip:~# screen
   c=IN IP4 198.58.99.250
2020-12-14 00:04:16.141587 [DEBUG] switch_core_state_machine.c:621 (sofia/external/12145551212) State CONSUME_MEDIA going to sleep
   t=0 0
   m=audio 22602 RTP/AVP 0 8 102 101
   a=rtpmap:0 PCMU/8000
   a=rtpmap:8 PCMA/8000
   a=rtpmap:102 SPEEX/8000
   a=rtpmap:101 telephone-event/8000
   a=fmtp:101 0-16
   a=ptime:20
   ------------------------------------------------------------------------
2020-12-14 00:04:16.141587 [DEBUG] sofia.c:6933 Channel sofia/external/12145551212 entering state [calling][0]
recv 355 bytes from udp/[216.53.4.1]:5060 at 00:04:16.447428:
   ------------------------------------------------------------------------
   SIP/2.0 100 Trying
   Via: SIP/2.0/UDP 198.58.99.250:5080;branch=z9hG4bK9DQSS9r0QS78c;received=198.58.99.250;rport=5080
   From: "" <sip:0000000000@198.58.99.250>;tag=52X35SSgpQtrB
   To: <sip:12145551212@216.53.4.1:5060>
   Call-ID: bf3b677f-b842-1239-b3a8-da7d13be054f
   Contact: <sip:216.53.4.1:5060>
   CSeq: 29398336 INVITE
   Server: sbc_5
   Content-Length: 0

   ------------------------------------------------------------------------
recv 419 bytes from udp/[216.53.4.1]:5060 at 00:04:16.501784:
   ------------------------------------------------------------------------
   SIP/2.0 503 Service Unavailable
   Via: SIP/2.0/UDP 198.58.99.250:5080;branch=z9hG4bK9DQSS9r0QS78c;received=198.58.99.250;rport=5080
   From: "" <sip:0000000000@198.58.99.250>;tag=52X35SSgpQtrB
   To: <sip:12145551212@216.53.4.1:5060>;tag=sbcsipuas_1_C20736_20201213190416427_ucs02sb04
   Call-ID: bf3b677f-b842-1239-b3a8-da7d13be054f
   Contact: <sip:216.53.4.1:5060>
   CSeq: 29398336 INVITE
   Server: sbc_5
   Content-Length: 0

   ------------------------------------------------------------------------
send 371 bytes to udp/[216.53.4.1]:5060 at 00:04:16.501891:
   ------------------------------------------------------------------------
   ACK sip:12145551212@216.53.4.1:5060 SIP/2.0
   Via: SIP/2.0/UDP 198.58.99.250:5080;rport;branch=z9hG4bK9DQSS9r0QS78c
   Max-Forwards: 70
   From: "" <sip:0000000000@198.58.99.250>;tag=52X35SSgpQtrB
   To: <sip:12145551212@216.53.4.1:5060>;tag=sbcsipuas_1_C20736_20201213190416427_ucs02sb04
   Call-ID: bf3b677f-b842-1239-b3a8-da7d13be054f
   CSeq: 29398336 ACK
   Content-Length: 0

   ------------------------------------------------------------------------
2020-12-14 00:04:16.241578 [DEBUG] sofia.c:6933 Channel sofia/external/12145551212 entering state [terminated][503]
2020-12-14 00:04:16.241578 [NOTICE] sofia.c:7961 Hangup sofia/external/12145551212 [CS_CONSUME_MEDIA] [NORMAL_TEMPORARY_FAILURE]
2020-12-14 00:04:16.241578 [DEBUG] switch_core_state_machine.c:543 (sofia/external/12145551212) Running State Change CS_HANGUP
2020-12-14 00:04:16.241578 [DEBUG] switch_core_state_machine.c:809 (sofia/external/12145551212) Callstate Change DOWN -> HANGUP
2020-12-14 00:04:16.241578 [DEBUG] switch_core_state_machine.c:811 (sofia/external/12145551212) State HANGUP
2020-12-14 00:04:16.241578 [DEBUG] mod_sofia.c:437 Channel sofia/external/12145551212 hanging up, cause: NORMAL_TEMPORARY_FAILURE
2020-12-14 00:04:16.241578 [DEBUG] switch_core_state_machine.c:60 sofia/external/12145551212 Standard HANGUP, cause: NORMAL_TEMPORARY_FAILURE
2020-12-14 00:04:16.241578 [DEBUG] switch_core_state_machine.c:811 (sofia/external/12145551212) State HANGUP going to sleep
2020-12-14 00:04:16.241578 [DEBUG] switch_core_state_machine.c:578 (sofia/external/12145551212) State Change CS_HANGUP -> CS_REPORTING
2020-12-14 00:04:16.241578 [DEBUG] switch_core_state_machine.c:543 (sofia/external/12145551212) Running State Change CS_REPORTING
2020-12-14 00:04:16.241578 [DEBUG] switch_core_state_machine.c:897 (sofia/external/12145551212) State REPORTING
2020-12-14 00:04:16.241578 [DEBUG] switch_ivr_originate.c:3750 Originate Resulted in Error Cause: 41 [NORMAL_TEMPORARY_FAILURE]