View source for Out of idle IAX2 threads

If you see something similiar like this in asterisk CLI:

   [*CLI> [Oct 24 22:56:55] ESC[1;33;40mNOTICEESC[0;37;40m[6404]: ESC[1;37;40mchan_iax2.c
   ESC[0;37;40m:ESC[1;37;40m6691ESC[0;37;40mESC[1;37;40msocket_readESC[0;37;40m: ^@'''Out of idle IAX2 threads for I/O, pausing!'''

That means You need increase '''iaxthreadcount''' & '''iaxmaxthreadcount''' values in '''/etc/asterisk/iax.conf''' . 

Defaults for these to variables are ;  
   iaxthreadcount = 10
   iaxmaxthreadcount = 100

Change to something 'bigger'
   
   iaxthreadcount = 100
   iaxmaxthreadcount = 1000

That should be fine, if you still see same error, try increasing values for these two variables.

Don't forget to do 

 /etc/initd./asterisk reload 

after that.