Unable To Create Channel Of Type SIP cause 20–Subscriber Absent

Unable To Create Channel Of  Type ‘SIP’

Topic: Unable To Create Channel Of Type SIP cause 20–Subscriber Absent

Unable To Create Channel Of Type SIP cause 20


   SIP (Session Initiation Protocol) is a protocol used in VoIP communications, allowing users to make voice and video calls, mostly for free. SIP allows people around the world to communicate using their computers and mobile devices over the internet.
  Asterisk vs SIP/PJSIP
The SIP Channel Module enables Asterisk to communicate via VoIP with SIP telephones and exchanges. Asterisk is able to act as: a SIP client: This means that Asterisk registers as a client to another SIP server and receives and places calls to this server, Also asterisk act as a SIP server: this means that other sip client like softphone, iPhone register as client and dial out via asterisk server.

  Issue: Unable to create channel of type SIP

       You might receive this error "unable to create channel of type SIP" in asterisk cli while dialing out from a Client or other mode of calling via asterisk server.

  Possible Cause of this Error:

    Below are the possible cause of this error
    1. The SIP Trunk Registered in the asterisk server is not active.
    2. The SIP endpoint Dialed is not active
    3. Right SIP Peer Name not set in Dialplan

   1. SIP Trunk Status

    Make sure the SIP trunk configured in the asterisk server is registered and reachable as a peer.
Type the below command in the asterisk cli to check the sip peer status

asterisk -vvvvr
sip show peers
the Above command output should show the peer is reachable with OK status
sip show registry
sip show registry
the above command should show the trunk peer is registered with the provider.

**note command to go to asterisk cli is  asterisk -vvvvvr

If the above commands shows that sip trunk not registered check the below conditions

Sip trunk settings in sip.conf file

sip trunk ip is reachable from the asterisk server

SIP Ports(5060) are opened in your server, router/firewall and ISP

   2. SIP Endpoint Status

    You may face similar issue if you are dialing to another SIP extension and the destination extension is not registered or not reachable via asterisk server.

To check the SIP endpoint status in asterisk type below command

sip show peers

Check Asterisk sever is reachable from those SIP clients, also check they are using right username ,password and Domain in registration settings.

   3. Dialplan SIP peer name misspelled.

    If you are not mentioned the actual name of the SIP peer in the dialplan, you will receive this error "unable to create channel of typ SIP"

Make sure you have entered a proper name of sip trunk context in dialplan as mentioned in the sip.conf 

for eg: you sip trunk name entered as voip1 in your sip.conf

then make sure you have entered same in your dialplan


exten => _9X.,1,Dial(SIP/${EXTEN:1}/voip1)
exten => _9X.,2,Hangup()


    For professional support reach me on skype:striker24x7

  • Ajit Kumar
    Ajit Kumar April 4, 2022 at 10:36 AM

    Unable To Create Channel Of Type ‘SIP’ (cause 20 – Subscriber Absent)

Add Comment
comment url