Thanks again for your reply Matt, and I'm really enbarrased for my stupid copy&paste mistake.
Is there a documentation of the columns that can be exported? I don't understand why I could "select some columns via &columns=column1,column2" since, as far as I can see, always all of the columns are exported and I can only hide the ones from which I know the names of. Also I can only seem to hide the whole actionDetails and not just some if those columns (like pageIdAction, generationTime and icon).
Is there a documentation of the columns that can be exported? I don't understand why I could "select some columns via &columns=column1,column2" since, as far as I can see, always all of the columns are exported and I can only hide the ones from which I know the names of. Also I can only seem to hide the whole actionDetails and not just some if those columns (like pageIdAction, generationTime and icon).