Vertical scroll not working

xD, and I have been doing every tutorial to learn the software. I'm doing a project for my school to create a wireframe for a mobile app. I used the vertical scroll option, not sure what I am doing wrong, but the scroll doesn't work when I share my prototype or review the artwork in the preview. I have a mouse, I'm not doing it with my touchpad, I'm following every single step of the tutorial of how scroll works, and it seems very straight forward. If anyone can help me, I will appreciate it.

Jackie Lackenbacher