Callers cant hear

I have a trixbox freepbx running version and it has been working great for a long time and now has decided to stop working. The first problem that started happening was users were unable to access voicemail. I rebuilt the voicemail boxs and still did not work. Would still email the voicemail and work fine. A couple days later now when a end user calls in you pickup the handset and you can hear them but they cannot hear you. If you call internal extension you can not hear either party. I am not very familiar with trixbox since I inherited this system so anybody have any ideas?