From that ADSB status window, click "Options" and then "Change Selected Device". Is it currently set to AUTO-DETECT? If so, try changing it to Stratux/Flightbox and see if there's any change. (And if it's set to Stratux/Flightbox, try changing it to AUTO-DETECT.)
You said you were able to log into the Stratux web interface, so I think this question is already answered, but just to be sure--confirm the tablet is connected to the Stratux's wifi before you launch iFly?
Without a GPS or AHRS onboard, and likely without a connection to any ADSB ground towers if you're trying to test this connection from home, the Stratux probably doesn't have any data to send to iFly. I'm not sure if that makes any difference in how iFly reports whether it's connected or not.