Увидел в INVITE Media Attribute (a): crypto. Отключите SRTP и должно заработать.
Session Initiation Protocol (INVITE)
Request-Line: INVITE sip:
[email protected]:5060 SIP/2.0
Message Header
Via: SIP/2.0/UDP 192.168.254.9:5060;branch=z9hG4bK-524287-1---49a0a74b1c544424;rport
Max-Forwards: 70
Contact: <sip:192.168.254.9:5060>
To: <sip:
[email protected]:5060>
From: "Nikolay"<sip:192.168.254.9:5060>;tag=3f57582e
Call-ID: qNrWpyVNs1qK7wGU6lq_4A..
CSeq: 1 INVITE
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REGISTER, SUBSCRIBE, NOTIFY, REFER, INFO, MESSAGE, UPDATE
Content-Type: application/sdp
Supported: replaces, timer
Content-Length: 626
Message Body
Session Description Protocol
Session Description Protocol Version (v): 0
Owner/Creator, Session Id (o): 3cxPS 2102102755115008 22340970674651137 IN IP4 192.168.254.9
Session Name (s): 3cxPS Audio call
Connection Information (c): IN IP4 192.168.254.9
Time Description, active time (t): 0 0
Media Description, name and address (m): audio 7168 RTP/SAVP 0 8 9 3 101
Media Attribute (a): rtpmap:0 PCMU/8000
Media Attribute (a): rtpmap:8 PCMA/8000
Media Attribute (a): rtpmap:9 G722/8000
Media Attribute (a): rtpmap:3 GSM/8000
Media Attribute (a): rtpmap:101 telephone-event/8000
Media Attribute (a): crypto:1 AES_CM_128_HMAC_SHA1_80 inline:SNmnQ7qheobi7wTyjdfRSEoDJihH0UH9jRv1C0Uu
Media Attribute (a): crypto:2 AES_CM_128_HMAC_SHA1_32 inline:ecoVKLueTelPn7WlwoZZz4eqAmpL3KlAHiIpTrI1
Media Attribute (a): sendrecv
Media Description, name and address (m): audio 7168 RTP/AVP 0 8 9 3 101
Media Attribute (a): rtpmap:0 PCMU/8000
Media Attribute (a): rtpmap:8 PCMA/8000
Media Attribute (a): rtpmap:9 G722/8000
Media Attribute (a): rtpmap:3 GSM/8000
Media Attribute (a): rtpmap:101 telephone-event/8000
Media Attribute (a): sendrecv