Hi, During proxy authentication, I got "mandatory IE missing" error in the response as shown below. How this error can be resolved? recv 585 bytes from udp/[209.82.10.250]:1898 at 15:31:39.933782: ------------------------------------------------------------------------ INVITE sip:9999@209.82.10.235 SIP/2.0 Via: SIP/2.0/UDP 209.82.10.250:1091 From: HC-Desktop <sip:1002@209.82.10.235>;tag=55409708 To: sip:9999@209.82.10.235 Contact: sip:1002@209.82.10.250:1091 Call-ID: 8e6df5d2-0367-43d9-bda8-f51a94033473@192.168.10.31 CSeq: 421988828 INVITE Content-Length: 187 Content-Type: application/sdp User-Agent: HelpCaster SoftPHONE Supported: com.hearme.mux v=0 o=HelpCaster 153553387 153553387 IN IP4 192.168.10.31 s=HelpCaster c=IN IP4 209.82.10.250 t=0 0 m=audio 8002 RTP/AVP 0 4 101 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 ------------------------------------------------------------------------ send 294 bytes to udp/[209.82.10.250]:1091 at 15:31:39.934100: ------------------------------------------------------------------------ SIP/2.0 100 Trying Via: SIP/2.0/UDP 209.82.10.250:1091 From: HC-Desktop <sip:1002@209.82.10.235>;tag=55409708 To: sip:9999@209.82.10.235 Call-ID: 8e6df5d2-0367-43d9-bda8-f51a94033473@192.168.10.31 CSeq: 421988828 INVITE User-Agent: FreeSWITCH-mod_sofia/1.0.2-hacked Content-Length: 0 ------------------------------------------------------------------------ send 746 bytes to udp/[209.82.10.250]:1091 at 15:31:39.938913: ------------------------------------------------------------------------ SIP/2.0 407 Proxy Authentication Required Via: SIP/2.0/UDP 209.82.10.250:1091 From: HC-Desktop <sip:1002@209.82.10.235>;tag=55409708 To: <sip:9999@209.82.10.235>;tag=K83mZmZH8g3Hr Call-ID: 8e6df5d2-0367-43d9-bda8-f51a94033473@192.168.10.31 CSeq: 421988828 INVITE User-Agent: FreeSWITCH-mod_sofia/1.0.2-hacked Accept: application/sdp Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, PRACK, MESSAGE, SUBSCRIBE, NOTIFY, REFER, UPDATE, REGISTER, INFO, PUBLISH Supported: timer, precondition, path, replaces Allow-Events: talk, presence, dialog, call-info, sla, include-session-description, presence.winfo, message-summary, refer Proxy-Authenticate: Digest realm="209.82.10.235", nonce="248a2800-7fd2-4a6f-8082-5d1731f3cf54" Content-Length: 0 ------------------------------------------------------------------------ recv 280 bytes from udp/[209.82.10.250]:1898 at 15:31:39.949517: ------------------------------------------------------------------------ ACK sip:9999@209.82.10.235 SIP/2.0 Via: SIP/2.0/UDP 209.82.10.250:1091 From: HC-Desktop <sip:1002@209.82.10.235>;tag=55409708 To: <sip:9999@209.82.10.235>;tag=K83mZmZH8g3Hr Call-ID: 8e6df5d2-0367-43d9-bda8-f51a94033473@192.168.10.31 CSeq: 421988828 ACK Content-Length: 0 ------------------------------------------------------------------------ recv 584 bytes from udp/[209.82.10.250]:1898 at 15:31:39.953137: ------------------------------------------------------------------------ INVITE sip:9999@209.82.10.235 SIP/2.0 Via: SIP/2.0/UDP 209.82.10.250:1091 From: HC-Desktop <sip:1002@209.82.10.235>;tag=55409708 To: sip:9999@209.82.10.235 Contact: sip:1002@209.82.10.250:1091 Call-ID: 8e6df5d2-0367-43d9-bda8-f51a94033473@192.168.10.31 CSeq: 421988829 INVITE Content-Length: 187 Content-Type: application/sdp User-Agent: HelpCaster SoftPHONE Supported: com.hearme.mux Proxy-Authorization: Digest username="1002",realm="209.82.10.235",nonce="248a2800-7fd2-4a6f-8082-5d1731f3cf54",response=" d1614cd024acab0b794751285f5cb1fe",uri="sip:9999@209.82.10.235" ------------------------------------------------------------------------ send 294 bytes to udp/[209.82.10.250]:1091 at 15:31:39.953336: ------------------------------------------------------------------------ SIP/2.0 100 Trying Via: SIP/2.0/UDP 209.82.10.250:1091 From: HC-Desktop <sip:1002@209.82.10.235>;tag=55409708 To: sip:9999@209.82.10.235 Call-ID: 8e6df5d2-0367-43d9-bda8-f51a94033473@192.168.10.31 CSeq: 421988829 INVITE User-Agent: FreeSWITCH-mod_sofia/1.0.2-hacked Content-Length: 0 ------------------------------------------------------------------------ send 696 bytes to udp/[209.82.10.250]:1091 at 15:31:39.956016: ------------------------------------------------------------------------ SIP/2.0 480 Temporarily Unavailable Via: SIP/2.0/UDP 209.82.10.250:1091 From: HC-Desktop <sip:1002@209.82.10.235>;tag=55409708 To: <sip:9999@209.82.10.235>;tag=mHXD1FgN5SS4K Call-ID: 8e6df5d2-0367-43d9-bda8-f51a94033473@192.168.10.31 CSeq: 421988829 INVITE User-Agent: FreeSWITCH-mod_sofia/1.0.2-hacked Accept: application/sdp Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, PRACK, MESSAGE, SUBSCRIBE, NOTIFY, REFER, UPDATE, REGISTER, INFO, PUBLISH Supported: timer, precondition, path, replaces Allow-Events: talk, presence, dialog, call-info, sla, include-session-description, presence.winfo, message-summary, refer Reason: Q.850;cause=96;text="MANDATORY_IE_MISSING" Content-Length: 0 ------------------------------------------------------------------------ recv 280 bytes from udp/[209.82.10.250]:1898 at 15:31:39.964632: ------------------------------------------------------------------------ ACK sip:9999@209.82.10.235 SIP/2.0 Via: SIP/2.0/UDP 209.82.10.250:1091 From: HC-Desktop <sip:1002@209.82.10.235>;tag=55409708 To: <sip:9999@209.82.10.235>;tag=mHXD1FgN5SS4K Call-ID: 8e6df5d2-0367-43d9-bda8-f51a94033473@192.168.10.31 CSeq: 421988829 ACK Content-Length: 0 Thanks!