Asterisk: Cannot send Instant messaging using PJSIP (415 Unsupported Media Type)

i have setup a realtime asterisk using PJSIP, i have configured some accounts, i see that they are well registered, but when i try to send Instant message from one peer to another, PJSIP resend Unsupported Media Type herein a trace

Via: SIP/2.0/UDP;branch=z9hG4bK2754b2334d6baa33fd7459a0abb4ca57
Via: SIP/2.0/TLS;branch=z9hG4bKb38169af55b04e81d9ace924f9f77da1343633;rport
From: "U2" <>;tag=2904885357
To: <>
Call-ID: 3c9473f85da212a9584541502acaf750@
CSeq: 3810 MESSAGE
Max-Forwards: 69
Accept: text/plain,application/im-iscomposing+xml
Content-Type: application/im-iscomposing+xml
Content-Length: 401

<?xml version='1.0' encoding='UTF-8' standalone='no' ?><isComposing xmlns="urn:ietf:params:xml:ns:im-iscomposing" xmlns:xsi="" xsi:schemaLocation="urn:ietf:params:xml:ns:im-composing iscomposing.xsd" name="{////90927765-7e47-4202-96ec-a31191c895d2}"><state>idle</state><list><entry uri="" cp:copyControl="to" /></list></isComposing>

<--- Transmitting SIP response (526 bytes) to UDP: --->

SIP/2.0 415 Unsupported Media Type
Via: SIP/2.0/UDP;rport=5060;received=;branch=z9hG4bK2754b2334d6baa33fd7459a0abb4ca57
Via: SIP/2.0/TLS;rport;branch=z9hG4bKb38169af55b04e81d9ace924f9f77da1343633
Call-ID: 3c9473f85da212a9584541502acaf750@
From: "U2" <>;tag=2904885357
To: <>;tag=z9hG4bK2754b2334d6baa33fd7459a0abb4ca57
CSeq: 3810 MESSAGE
Server: Platform PBX
Content-Length:  0

i have inserted my users like this:

insert into ps_endpoints (id, transport, aors, auth, context, disallow,  allow, direct_media, message_context) values ('user1', 'transport-udp', 'user1', 'user1', 'testing', 'all', 'gsm,alaw,ulaw,g729', 'no', 'astsms');
insert into ps_auths (id,auth_type,md5_cred, realm, username)VALUES ('user1','md5','55528a840cfcd2083966e679c8f968f9','', 'user1');
insert into ps_aors (id, max_contacts) values ('user1', 1);

pjsip tells me that it can’t support application/im-iscomposing+xml, pjsip is supposed to support RFC 3994.

my pjsip.conf

rtcachefriends = yes

Non mapped elements end

type = global
user_agent = Platform PBX

type = transport
protocol = udp
bind =

installed pjsip libraries

What i’m missing?

Neither chan_pjsip or chan_sip support the “application/im-iscomposing+xml” media type. Thus why it responds with unsupported media type. Only “text/plain” is supported.