I have set up the 3CX (version 12) system and everything looks good so far. I set up the ext and added these phones from the drop down menu. Changed the config on the phones ( they were used on a 3 Com system before) to use the new server for provisioning. They can't seem to find the 3CX machine. The error message on the phone is can not find the server, reverting to previous configuration. Is there something I am missing on the 3CX configuration? Also are the 501's even supported? They aren't listed on the site yet the option is in the configuration page.