The procedure you are using is correct but it is sometimes tricky to setup constraints. Your view needs to have either implicit or explicit width and height. Then it needs to be inserted into scroll view and have all 4 border constraints setup.
Looking at your project you have missed a few constraints. To debug a view like that it is easiest to first set it up outside the scroll view. Take your view outside it and setup leading and top constraints to it's superview. Now modify your constraints until you see a desired result.
For your specific case I used:
- View width equals to superview width
- First label leading and top are pinned to superview leading and top
- First text field leading to First label trailing
- First text field trailing to Superview trailing
- First text field center vertically to First label
- Outlet label leading to Superview
- Outlet label trailing to Superview
- Outlet label top to First label bottom
- Second label leading to Superview leading
- Second label top to Outlet label bottom
- Second text field leading to Second label trailing
- Second text field trailing to Superview trailing
- Second text field center vertically to Second label
- Second label bottom to Superview bottom
After all these are set I have a nicely layout view without a scroll view. There should be no errors visible.
Now add a scroll view. Pin it to leading, trailing, top and bottom. Then drag your view inside your scroll view and this view to scrollview leading, trailing, top and bottom and set equal width between your view and your scrollview. That should be it.