DJM-REC streaming issue

First time using this app in conjunction with djm-750mk2 (updated firmware 1.04) and iPhone X / iOS 13.3.1, coming out of the send / return usb, the recording sounded great; however when streaming on Periscope (or any platform) the audio switched to phone mic and picked up ambient room noise, instead of direct off mixer. What am I doing wrong here?