Problem with calls on a landline

Hi everyone,
I had this issue from a day to another, so i hope you can help me cause i need to fix it as soon as possible, so here we go.
I have a switchboard with asterisk and freePBX, when an incoming call is send to my switchboard, phone doesnt detect the call, but the phone can make calls internally and externally, but we have the problem when someone calls to me, ive checked files on PBX comparing with other switchboard that works well but i cant find the error.
Thanks in advance.

You might try the FreePBX forums. Also some more logs might help.