Problems with calling out (SIP Trunk and External Extension)

Hello, I have a little problem.
I have the latest version of Trixbox and I have some problems with outgoing calls/

  1. I have the SIP trunk to the “”, it work perfect for incoming calls, but I can’t call out ( I get the message: "All sockets are busy now, please … "
  2. I try to define “Remote SIP Extension” (according to rules at: I have the same problem, I can call from the extension, but I can’t call to extension.

My Trixbox is connected to the Internet through the CISCO PIX 501 E FireWall (with static NAT). For testing purposes, I try to open my FireWall “Any-to-Any”, but I got the same result.
Maybe somebody have any ideas what and where I need tho check/fix?