I have an employee who works from home. he is supposed to use only his 3CX for windows client to connect to the PBX. so in the extension the phone model is empty, the MAC address is empty. in the 3cx phone tab i set the options i need and then i send this employee the welcome email. the provisioning file attached to the welcome email is empty and contains nothing at all how do i send a 3cxconfig file to this extension?