Ipad to usb to ds sr

working: IOS12 ipad plays hi res via usb to iFi nano dsd using latest gen camera adapter which has a power input as well as the usb out. not working: the exact same set up does not play to dstream, just unplug usb from ifi and into dstream. the ipad says a ps audio dac is connected, but no sound. thing is, the bit rate display on dstream is correct. it shows 385k, 44.1, etc depending on the source. the player shows the song progressing, everything look to be working, but no sound, its like it is muted. im using a powered usb hub, as well as powering the camera adapter. no warnings from ipad about power load on usb. i confirmed it is not muted, the light is green. why does the iFi (and chord and other dacs) work but not dstream? does dstream automatically mute usb audio under some conditions?

really appreciate any advice on this.