I went through this with a customer before I was pointed to this thread by @lfulgenzi .
Digging through the Jabber log on my end , for my MRA customers , what I could see is that whatever mechanism grabs the socket details for the SIP connection is not able to determine the local port. It defaults to 0 I guess in that case. Jabber is actually okay with this and sends it off to the Expressway. The Expressway is also okay with this, and replies with the proxy auth challenge (407).
In the log, we can see the via line showing the client's IP and a port of 0, which Jabber notes is a bad message and discards it. It goes through the unregister process internally, and then starts over to no avail. If you get the WAN IP of the customer, you can see timeouts and similar as Jabber sends nothing to the Expressway, it just discontinues the conversation.
On the UCM end, the logging looks tends to look like:
subscriber.ucm.log:May 18 15:05:33 subscriber.ucm May 18 2021 19:05:33.259 UTC : %UC_PHONE-6-LastOutOfServiceInformation: %[DeviceName=CSFUSER][DeviceIPv4Address=192.168.2.102 / 0][IPv4DefaultGateway=][DeviceIPv6Address=][IPv6DefaultGateway=][ModelNumber=CSF][NeighborIPv4Address=][NeighborIPv6Address=][NeighborDeviceID=][NeighborPortID=][DHCPv4Status=1][DHCPv6Status=3][TFTPCfgStatus=1][DNSStatusUnifiedCM1=1][DNSStatusUnifiedCM2=1][DNSStatusUnifiedCM3=1][VoiceVLAN=0][UnifiedCMIPAddress=subscriber.ucm][LocalPort=0][TimeStamp=1621364729][ReasonForOutOfService=14][UNKNOWN_PARAMNAME:ReasonForOutOfServiceText=cm-closed-tcp][UNKNOWN_PARAMNAME:ActiveInterface=Wired][LastProtocolEventSent=][LastProtocolEventReceived=Rcvd:SIP/2.0 407 Proxy Cseq:101 REGISTER CallId:acde4800-11220002-48661a04-273621be@192.168.2.102 ][AppID=Cisco CallManager][ClusterID=CCM01-Cluster][NodeID=loader110b.cit.buffalo.edu]: Information related to the last out-of-service event
In the jabber.log file you'll find the 407 that's referenced in the "LastProtocolEventReceived" field to be the one that triggers the bad message on Jabber's end:
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [/core/sipstack/ccsip_platform_tcp.c(750)] [csf.sip-call-control] [sip_tcp_newmsg_to_spi] - SIP : sip_tcp_newmsg_to_spi : Sip message rcv: message=
[SIP][MSG] [SOCK][.]<--- SIP/2.0 407 Proxy Authentication Required
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [/sipcc/core/sipstack/ccsip_debug.c(1121)] [csf.sip-call-control] [platform_print_sip_msg] - sipio-recv<--- SIP/2.0 407 Proxy Authentication Required
Via: SIP/2.0/TLS 192.168.86.214:0;branch=z9hG4bK501c3fc0;received=66.99.69.69;rport=58694
Call-ID: a861b526-89ce02a8-76969686-6bfdb125@192.168.86.214
CSeq: 402 REGISTER
From: <sip:1234567@subscriber.ucm>;tag=a860b62689ce024f5c792b86-171899d8
To: <sip:1234567@subscriber.ucm>;tag=1c52efaac0c6b092
Server: TANDBERG/4144 (X12.6.2)
Proxy-Authenticate: Digest realm="expressway-e.cluster", nonce="...", opaque="...", stale=FALSE, algorithm=MD5, qop="auth"
Proxy-Authenticate: Bearer realm="expressway-e.cluster"
Content-Length: 0
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [/sipcc/core/sipstack/ccsip_debug.c(1121)] [csf.sip-call-control] [platform_print_sip_msg] - ::End-Of-Sip-Message::
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [/core/sipstack/ccsip_platform_tcp.c(765)] [csf.sip-call-control] [sip_tcp_newmsg_to_spi] - [[MESSAGE_1.0]]: [69.66.99.69] --> SIP/2.0 407 Proxy Authentication Required() --> [SIPCC] :
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [sipstack/sip_transport_connection.c(312)] [csf.sip-call-control] [sip_transport_connection_on_socket_read] - [SIP][CONN][] socket(75) received msg
[SIP][MSG] [CONN][.]<-----| SIP msg |------[SOCK][75]
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [sipstack/sip_transport_connection.c(166)] [csf.sip-call-control] [sip_transport_connection_event_post] - [SIP][CONN][0] send event to sess recvMsg(2).
[SIP][MSG] [SESS][0]<-----| recvMsg |------[CONN][0]
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [re/sipstack/sip_transport_session.c(866)] [csf.sip-call-control] [sip_transport_session_event_post] - [SIP][SESS][0] post event recvMsg(3) to ob(1)
[SIP][MSG] [TRANS][1]<-----| recvMsg |------[SESS][0]
2021-05-12 09:54:51,301 WARN [0x0000700047ed7000] [onewrapper/ccapi_plat_api_impl.cpp(2555)] [csf.ecc.sipcc] [platSendMetricEventSIP] - Dummy implementation of platSendMetricEventSIP is called.
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [/core/sipstack/ccsip_common_util.c(1119)] [csf.sip-call-control] [ccsip_store_rcvd_msg_for_alarm] - SIPCC-SIP_MSG_SEND: ccsip_store_rcvd_msg_for_alarm: local_uuid: , remote_uuid: , type:1, state:17
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [/core/sipstack/ccsip_common_util.c(1121)] [csf.sip-call-control] [ccsip_store_rcvd_msg_for_alarm] - SIPCC-SIP_MSG_SEND: ccsip_store_rcvd_msg_for_alarm: Rcvd:SIP/2.0 407 Proxy Cseq:402 REGISTER CallId:a860b626-89ce02a8-76691186-6bfdb125@192.168.86.214
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [p/sipcc/core/sipstack/ccsip_debug.c(244)] [csf.sip-call-control] [ccsip_dump_recv_msg_info] - SIPCC-SIP_MSG_RECV: ccsip_dump_recv_msg_info: <69.66.99.69:0 >:407 Pro: <sip:1234567@subscriber.ucm>;tag=a860b62689ce024f5c792b86-171899d8 :402 REGISTER::a860b626-89ce02a8-76691186-6bfdb125@192.168.86.214
2021-05-12 09:54:51,301 DEBUG [0x0000700047ed7000] [pp/sipcc/core/sipstack/ccsip_pmh.c(3186)] [csf.sip-call-control] [sippmh_parse_via] - sippmh_parse_via: Invalid port number in Via
2021-05-12 09:54:51,301 ERROR [0x0000700047ed7000] [p/sipcc/core/sipstack/ccsip_task.c(1885)] [csf.sip-call-control] [SIPTaskProcessSIPMessage] - SIP : SIPTaskProcessSIPMessage : sip_sm_determine_ccb(): bad response. Dropping message.
Looks like you can verify this by searching for "Invalid port number in Via"
