How to Loop? (Pro)

Hi, I paid for the app to learn rhythm guitar for worship songs and am trying to use the loop feature on chords to practice the chorus.

Except, when I tap loop on the app, and move the window over the chorus, the app doesn’t actually play or loop the section I’ve highlighted. it keeps playing the first line of the song over and over, not the part highlighted . i tried it on my ipad and iPhone, i dont get it.

what am i doing wrong?