@Dashrender When your devices are shown as UNAVAILABLE but marked as REGISTERED, try to decrease the qualify frequency value on the technology profile assigned to your devices. For PJSIP is usually the "Default PJSIP Profile", for SIP, is usually the "Default SIP Profile".
About, One Way Audio, remember to configure the External Address and the local address on the SIP Settings or PJSIP Settings, depending on the technology you are using.