Callers can't call

Hey all!
Iv made some sip extentions in FreePBX and put them into phones, every thing seems OK. The problem now is that when some one tries to call from one phone to a nother it gives me a empty tone or says “The Person you a calling is unavaileble”.
the problem occured about a week ago or so after I restarted ssh.
I’d really appreciate if some one can help!

Im running Asterisk 1.4.24 with FreePBX on CentOS.