Cisco SPA112

I have a Cisco SPA112 thats worked well, all of a sudden it needs to be rebooted to see our freepbx box which is on the same LAN.

Gone through the basics NAT keep alive and other settings, how can i find more information out on whats happening.

Thanks

Can you share some more detail of what the extension is set like, and what the SPA112 is set like ? (anonymize the passwords/ext no.'s etc.)