Translation:
Why can't my iPad automatically rotate anymore even when the orientation lock is off?
My iPad doesn't spin anymore no matter what I do, even though the orientation lock is off.
What is the problem and what can I do?
To switch between Portrait and Landscape view, you generally only need to rotate the iPad to the desired screen orientation.
For newer models of iPad without a side-switch, you may need to disable your Screen Rotation Lock. To do so, you need to access the Control Centre; swipe downwards from the top-right corner of the screen - then tap the Screen Rotation lock icon:
If screen rotation proves to be problem with some Apps - and not others - you need to be aware that not all Apps are coded to operate in both Portrait and Landscape screen modes. Apps that have a fixed screen orientation will always appear in the orientation determined by the App Developer.