Incoming Fax fails

[gustavskii]

Hello

Incoming faxes fails

Here what I see in the Data>Fax>Faxes>Failed: (I replaced number with xxx)

<?xml version="1.0" encoding="UTF-8"?>
-<FAX>
-<INFO PAGES="0" FAX_ID="" CALLER_ID="xxx" CALLEE_ID="999">
<STARTTIME>20180912165940.849</STARTTIME>
<STOPTIME>20180912165945.202</STOPTIME>
<IMGFILE>fax_1536155496_no24.tif</IMGFILE>
<PDFFILE/>
<RCV_ERROR/>
</INFO>
<FLAGS>0</FLAGS>
</FAX>​

Here are logs that I see:

12/09/2018 12:59:40:676 | 6 | [CM503001]: Call(C:26701): Incoming call from Line:10004<<xxx to <sip:[email protected]:5060>
12/09/2018 12:59:40:676 | 6 | [CM500002]: Call(C:26701): Info on incoming INVITE from Line:10004<<xxx:
Invite-IN Recv Req INVITE from x.x.x.x:5060 tid=7m25m3QKUaS3m Call-ID=14554ae7-3150-1237-b1be-0ea6f44d244a:
INVITE sip:[email protected]:5060;rinstance=20c3ab28b3ad2d0b SIP/2.0
Via: SIP/2.0/UDP x.x.x.x;rport=5060;branch=z9hG4bK7m25m3QKUaS3m
Max-Forwards: 65
Contact: <sip:[email protected]:5060>
To: <sip:[email protected]:5060;rinstance=20c3ab28b3ad2d0b>
From: "xxx" <sip:[email protected]>;tag=DUSKQ4mjNeptQ
Call-ID: 14554ae7-3150-1237-b1be-0ea6f44d244a
CSeq: 128049726 INVITE
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE
Content-Disposition: session
Content-Type: application/sdp
Supported: path, replaces
User-Agent: provider_mode/1.6.19~64bit
Allow-Events: talk, hold, conference, presence, as-feature-event, dialog, line-seize, call-info, sla, include-session-description, presence.winfo, message-summary, refer
Privacy: none
P-Asserted-Identity: "xxx" <sip:[email protected]>
X-FS-Support: update_display,send_info
Content-Length: 224

v=0
o=SWITCH 1536739498 1536739499 IN IP4 x.x.x.x
s=SWITCH
c=IN IP4 x.x.x.x
t=0 0
m=audio 32082 RTP/AVP 0 101
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20

12/09/2018 12:59:40:678 | 6 | [CM503010]: Call(C:26701): Making route(s) from Line:10004<<xxx to <sip:[email protected]:5060>
12/09/2018 12:59:40:678 | 6 | [Flow] Call(C:26701): has built target endpoint: Fax:999 for call from L:26701.1[Line:10004<<xxx]
12/09/2018 12:59:40:678 | 6 | [CM503004]: Call(C:26701): Route 1: from L:26701.1[Line:10004<<xxx] to T:Fax:999@[Dev:sip:[email protected]:5483;rinstance=67de0f251d308a1c]
12/09/2018 12:59:40:678 | 6 | [CM503027]: Call(C:26701): From: Line:10004<<xxx ("xxx" <sip:[email protected]:5060>)  to  T:Fax:999@[Dev:sip:[email protected]:5483;rinstance=67de0f251d308a1c]
12/09/2018 12:59:40:702 | 10 | [CM503025]: Call(C:26701): Calling T:Fax:999@[Dev:sip:[email protected]:5483;rinstance=67de0f251d308a1c] for L:26701.1[Line:10004<<xxx]
12/09/2018 12:59:40:952 | 10 | [CM503002]: Call(C:26701): Alerting Fax:999 by contact <sip:[email protected]:5483>
12/09/2018 12:59:40:954 | 10 | L:26701.2[Fax:999] has joined to L:26701.1[Line:10004<<xxx]
12/09/2018 12:59:40:957 | 10 | [CM503007]: Call(C:26701): Line:10004<<xxx has joined, contact <sip:[email protected]:5060>
12/09/2018 12:59:40:958 | 10 | [CM503007]: Call(C:26701): Fax:999 has joined, contact <sip:[email protected]:5483>
12/09/2018 12:59:45:053 | 10 | Leg L:26701.1[Line:10004<<xxx] is terminated: Cause: BYE from x.x.x.x:5060
12/09/2018 12:59:45:056 | 10 | [CM503008]: Call(C:26701): Call is terminated
12/09/2018 12:59:45:056 | 10 | Leg L:26701.2[Fax:999] is terminated: Cause: BYE from local

Legend:
sip.address.my - my sip address
3cx.address.my - my 3cx address
sipusername - SIP username
y.y.y.y - 3cx IP address
x.x.x.x - provider IP address
xxx - number that is sending fax

Please help

 

[lneblett]

Not enough info. What is 999, a 3CX inbound FAX extension, a fax extension with an ATA or other t.38 capable device or simply a regular extension?

The INVITE is showing an audio codec, but it is also unknown if the there was a subsequent INVITE to t.38 and/or if the provider you use supports t.38.

 

[eddv123]

If T.38 is what you are using and it does not work or your provider does not support drop back to G711 pass through and see if this works.

Obviously this is subject to setup.

 

[gustavskii]

Provider supports T.38
999 is default fax extension, that was set up in "fax server" settings
I disabled fallback to G711, but it is still same

 

[eddv123]

I hope your system is not in the UK - this is our emergency number to the police.

So you are just using the Fax extension for inbound Faxing without a machine/FXS gateway ?

Please confirm.

 

[gustavskii]

We are in Canada, it shoudl be fine
Yes, without machine/FXS gateway

 

[NickD_3CX]

What @eddv123 said, we don't have enough info, but I can tell you what the most common reason is where inbound faxes to the fax server fail is, and how to check it.

1. First you will need a packet capture of a full inbound fax attempt. Open it with wireshark.
2. In the first INVITE, the provider will send audio codecs in the SDP, and 3CX will respond with a 200 OK, let's say using port 9020.
3. A few seconds will pass, then 3CX will send a INVITE to the provider requesting the switch to T38, this time though using the original port + 2, so port 9022. The provider should respond with ha 200 OK. (changing ports is valid)
4. At this point, 3CX will start send T38 packets from the new port (9022) and expecting to receive packets there too (provider did say 200 OK after all).
5. The most common thing is that the provider is not in fact sending UDP packets to the new port, but rather still to the old one.

Can't say for sure this is the case, but it is very common. There is not a lot 3CX can do about this and you should inform your provider.