The brushes are way too thin – Adobe Illustrator Draw Review

The app works great on my old IPhone 5c, but when I got my new iPhone 6s i tried to draw and noticed the brush was sooo thin. I was using the same format same brush(even when I maxed out the size of brush. So then I started editing the brush no luck. What do I do?
Review by TotallyNotViolet on Adobe Illustrator Draw.