In order for the scroll view to be able to determine its content size using auto layout, all its subviews must have an intrinsic content size. That means there must be an unbroken chain of constraints from edge to edge, and all views involved in determining the content size must have an intrinsic content size themselves. So UITextViews must have scrolling disabled, subviews with their own subviews must follow the same rules, etc.
If the scroll view should *not* use auto layout to determine its content size, then you should have one view that is the immediate child of the scroll view, and that view should have explicit width and height constraints (as well as being constrained with spacing 0 for top, bottom, leading and trailing).