title: How to configure asterisk instant messaging to work with linphone?
body: <p>I have followed the instructions provided in the answer of this thread <a href="https://stackoverflow.com/questions/23108706/how-to-configure-asterisk-instant-messaging">how to configure asterisk instant messaging</a> to configure the asterisk for instant messaging. However, the instant message feature doesn't seem to work. I am using asterisk version 11.16.0 and the soft-phone I used to test is linphone/blink/CSipSimple and the instant message feature doesn't work on either of them (Note: the voice call feature is working properly on all those soft-phone).</p>
  
  <p>On the asterisk server, I connected to its console using command "asterisk -rvvvvvvvvvvv" but didn't see any error/warning message on the asterisk console when sending the instant message on the soft-phone. Looking at the debug console of linphone (iOS version), I saw the following log:</p>
  
  <p>2015-09-14 16:30:50.464 linphone[1018:85779] I Skipping top route of initial route-set because same as request-uri.
  2015-09-14 16:30:50.465 linphone[1018:85779] I Changing [client] [MESSAGE] transaction [0x7f9dd3f1def0], from state [INIT] to [TRYING]
  2015-09-14 16:30:50.465 linphone[1018:85779] I channel [0x7f9dcb9e8400]: message sent to [UDP://192.168.103.138:5060], size: [422] bytes
  MESSAGE sip:6003@192.168.103.138 SIP/2.0
  Via: SIP/2.0/UDP 192.168.103.8:55607;branch=z9hG4bK.RYHnb2K0p;rport
  From: ;tag=V4jhkvcy7
  To: sip:6003@192.168.103.138
  CSeq: 20 MESSAGE
  Call-ID: crwxS4~~~w
  Max-Forwards: 70
  Supported: outbound
  Content-Type: text/plain
  Content-Length: 9
  Date: Mon, 14 Sep 2015 09:30:50 GMT
  User-Agent: LinphoneIphone/2.3-47-gb47c75d (belle-sip/1.4.1)</p>
  
  <p>hi there?
  2015-09-14 16:30:50.479 linphone[1018:85779] I channel [0x7f9dcb9e8400]: starting recv background task with id=[56].
  2015-09-14 16:30:50.479 linphone[1018:85779] I channel [0x7f9dcb9e8400]: received [437] new bytes from [UDP://192.168.103.138:5060]:
  SIP/2.0 404 Not Found
  Via: SIP/2.0/UDP 192.168.103.8:55607;branch=z9hG4bK.RYHnb2K0p;received=192.168.103.8;rport=55607
  From: ;tag=V4jhkvcy7
  To: sip:6003@192.168.103.138;tag=as5562adfb
  Call-ID: crwxS4~~~w
  CSeq: 20 MESSAGE
  Server: FPBX-AsteriskNOW-12.0.76(11.16.0)
  Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
  Supported: replaces, timer
  Content-Length: 0</p>
  
  <p>2015-09-14 16:30:50.480 linphone[1018:85779] I channel [0x7f9dcb9e8400] [437] bytes parsed
  2015-09-14 16:30:50.480 linphone[1018:85779] I Found transaction matching response.
  2015-09-14 16:30:50.481 linphone[1018:85779] I Changing [client] [MESSAGE] transaction [0x7f9dd3f1def0], from state [TRYING] to [COMPLETED]</p>
  
  <p>Is there anyone experience similar issue? Any idea on how I should do further troubleshooting to pinpoint the cause of the issue and fix it? It seems to me that something on the asterisk is not yet configured properly but without any error/warning on the console, I am not sure what else to do for further troubleshooting.</p>