Solved Content-Type ist missing on invites from queues

[mzao]

Hi,

If I call an extension (let's say 309) from another extension (for example 319), everything works as expected and the invite sent looks like:

(ip addresses are masked in this snippets)

INVITE sip:[email protected]:5950 SIP/2.0
Via: SIP/2.0/ ;branch=z9hG4bK-524287-1---ce415e143f6d2a19;rport
Max-Forwards: 70
Contact: <sip:[email protected]:5060>
To: <sip:[email protected]3cx.de>
From: "Frank:test 309 via grp"<sip:[email protected]:5060>;tag=57107144
Call-ID: e8au7X5t1_lD0llOZG_Gsg..
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: 417

v=0
o=3cxPS 417316470784 258637561857 IN IP4 0.0.0.0
s=3cxPS Audio call
c=IN IP4 176.9.78.145
t=0 0
m=audio 9072 RTP/AVP 3 18 9 0 8 112 101
a=rtpmap:3 GSM/8000
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=rtpmap:9 G722/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:112 opus/48000/2
a=fmtp:112 maxplaybackrate=16000;sprop-maxcapturerate=16000
a=rtpmap:101 telephone-event/8000
a=sendrecv


But if I put extension 309 as an agent in a queue (806), it looks like:

INVITE sip:[email protected]:5950 SIP/2.0
Via: SIP/2.0/ ;branch=z9hG4bK-524287-1---963ea455b736f25d;rport
Max-Forwards: 70
Contact: <sip:[email protected]:5060>
To: <sip:[email protected]3cx.de>
From: "test 309 via warteschleife:Frank"<sip:[email protected]:5060;nf=q>;tag=7f46f56e
Call-ID: WoRcDz0JmDNz9zkNaZjC1g..
CSeq: 1 INVITE
Alert-Info: <http://www.notused.invalidtld>;info=q806
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REGISTER, SUBSCRIBE, NOTIFY, REFER, INFO, MESSAGE, UPDATE
Supported: replaces, timer
Content-Length: 0

As result, the connected ip phone rejects this call with

Session 29029 has failed in leg L:27.3[Extn:309] ; Cause: 415 Unsupported Media Type/INVITE from 0.0.0.0:5950

Why is there no content-type and no sdp information sent, when a queue invites an extension and how can I fix that?

Thanks for all help.

Markus

 

[mzao]

3CX uses re-Invites when transferring calls from queues. This is the reason for the first INVITE without SDP information. As the used IP-Phone does not support re-Invites, it does not understand the INVITE without SDP information.

Solution: I've unchecked the option "support re-Invites" in the extension configuration on 3CX.

 

[VasilisV_3CX]

Great to see you've managed to solve the issue @mzao. Thanks for updating so that others who face similar issues may find the solution as well.