I couldnt find a techy student as such but I ran a android silumlator and tested the moodle app and lauched the the site via chrome. The results are the same: for android 7 below our site has the "connection is not private" issue on chrome and won't connect to site via the app. Site works find on Android 7 and on my PC. so, I don't think its a connection issue.
Pls note: the test site one of you sent works fine on those devices. So, there's something from the moodle site I should change? Pls help figure it out. thanks