Troubleshoot SIP (cause 20 - subscriber absent)

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

   

OVERVIEW:

You might get the above error while dialing over a SIP trunk or dialing another SIP Endpoint from SIP servers like asterisk

Possible Cause of this error:

1.Sip trunk not registered

2.SIP name not mentioned properly in Dialplan

1. Sip trunk Troubleshoot

Make sure your sip trunk got registered properly in Asterisk server
Goto Asterisk cli and type the below commands to check the status of SIP trunk registration

sip show peers

sip show registry

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

1a. 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. Dialplan Issue :

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

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

then make sure you have entered same in your dialplan

eg:  

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

exten => _9X.,2,Hangup()

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

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

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

Also check:
configure Gsm Gateway in asterisk
SIP Nat issue
Pri card configuration in asterisk