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.