Calls are not outgoing sometimes

Anybody know why calls are hang up after dialing password?, but is ocurr only some times not ever.
here i put the logs where I see Lastapp and lastdata as “Busy” and “3”

Calldate Channel Source Clid Lastapp Lastdata Dst
2015-11-25 12:59:06 SIP/553… 553 “Piere”<553> Busy 3 9xxxxxxx
2015-11-25 12:47:26 SIP/553… 553 “Piere”<553> Busy 3 9xxxxxxx

the asterisk console is not showings any error.

Any sugestion to fix?

PS: Sorry my English!!

We would need to see the complete console output and SIP log (sip set debug on) in order to have a real idea of what is going on.