Certain Pro Tools HDX interfaces, e.g. AVID HD OMNI are not usable as a system audio output while Pro tools is in use. In certain scenarios, this can prevent using ListenHub to reference system and DAW audio. 

Users running later versions of Pro Tools can utilise the new Audio Bridge core audio devices and AUX I/O as a workaround to reference within Pro Tools itself (Pro Tools 2022.9 or higher). 

For more information on the different workarounds available, please contact our support team.