No audio when change sip port

hello, anybody can help me to solve this: i have installed freepbx and test calls with remote extensions, all is ok when it is configured default sip port (5060), but when i change the port 5060 to a non standard port (12060) i do not have audio on calls. both remote extensions register with new port, the call complete but there is no audio.

i change the default sip port and restart asterisk so the system bind to the new port.

thanks your help.