I see some people have asked the same question but their solution did not work for me. Panning works fine when my MacBook Pro is not connected to StudioLive 16.0.2. I have assigned the main outputs to 15&16 on the Universal Control app (VSL software). I have seen this forum that someone suggested that one should bypass the Universal Control app. I even watched Youtube videos. My app version is 220.127.116.11437/5875 and my VSL software does not have the bypass option. Panning also works fine if physically turn the knobs on the Studiolive mixer. However my instruments on all the channels in Studio One do not pan. I tried making the main output mono-to no avail. I am running OS 10.13.3 High Sierra.