The Stylo 2 supports OTG. The Stylus 2 doesn't. Strange and regrettable, but true.
The Stylus 2 can be made OTG capable only by rooting it, then using Root Browser to navigate to
/sys/devices/soc/78db000.usb/power_supply/usb/usb_otg
changing state from 0 to 1, and saving,
then going to...