title: app_dial.c: dial_exec_full Unable to create channel type SIP (cause 20 Unknown)
body: <p>I for the first time trying to configure the asterisk on My Ubuntu Linux Machine .I installed the asterisk and on executing the following command i am getting this in my terminal...</p>
  
  <pre><code>root@ubuntu:~# asterisk -r
  Asterisk 1.8.4.4~dfsg-2ubuntu1.1, Copyright (C) 1999 - 2010 Digium, Inc. and others.
  Created by Mark Spencer &lt;markster@digium.com&gt;
  Asterisk comes with ABSOLUTELY NO WARRANTY; type 'core show warranty' for details.
  This is free software, with components licensed under the GNU General Public
  License version 2 and other licenses; you are welcome to redistribute it under
  certain conditions. Type 'core show license' for details.
   =========================================================================
  Connected to Asterisk 1.8.4.4~dfsg-2ubuntu1.1 currently running on ubuntu (pid = 1062)
  ubuntu*CLI&gt; 
  </code></pre>
  
  <p>Now i have updated <code>sip.conf</code> with following..</p>
  
  <pre><code>[general]
  port = 5060
  bindaddr = 0.0.0.0
  context = others
  
  [2000]
  type=friend
  context=my-phones
  secret=1234
  host=dynamic
  
  [2001]
  type=friend
  context=my-phones
  secret=1234
  host=dynamic
  </code></pre>
  
  <p>And here is my <code>extensions.conf</code></p>
  
  <pre><code>[others]
  
  [my-phones]
  exten =&gt; 2000,1,Dial(SIP/2000)
  exten =&gt; 2001,1,Dial(SIP/2001) 
  </code></pre>
  
  <p>Now for testing purpose i have downloaded <code>Twinkle</code> softphone and tried to configure the extension <code>2000</code> with Username <code>2000</code> and Domain <code>Localhost</code> .
  Now i after registering above in twinkle i tried to call Extension <code>2001</code> from Twinkle but it is giving following error into the <code>Asterisk CLI</code>..</p>
  
  <pre><code> [Apr  1 03:49:58] WARNING[2301]: app_dial.c:2041 dial_exec_full: Unable to create   channel of type 'SIP' (cause 20 - Unknown)
  </code></pre>
  
  <p>And here is Command <code>sip show peers</code> result in terminal..</p>
  
  <pre><code>  Name/username              Host                                    Dyn Forcerport ACL Port     Status     
    2000/2000                  127.0.0.1                                D          5061     Unmonitored 
    2001                       (Unspecified)                            D          0        Unmonitored 
    2 sip peers [Monitored: 0 online, 0 offline Unmonitored: 1 online, 1 offline]
  </code></pre>
  
  <p>Sip Registration Is also showing Zero..</p>
  
  <pre><code>ubuntu*CLI&gt; sip show registry
  Host                                    dnsmgr Username       Refresh    State                Reg.Time                 
  0 SIP registrations.
  </code></pre>
  
  <p>This is all about my problem..I am very novice to asterisk and Linux both and have been struck badly into this situation.
  Please help me to resolve this.</p>