The problem is that you're using a storyboard with auto layout turned on as the source of your prototype cell with the scroll view inside it. Hence your attempt to set the scroll view's content size manually is failing. Either use internal constraints to set the contents size, or else create and configure the scroll view and its contents entirely in code so that auto layout doesn't apply to them, or else use a separate .xib as the source of your cell (so that you can turn off auto layout there).
I was able to get your scroll view working using constraints in your storyboard. I had to give both the scroll view and the label appropriate constraints.