D7, Bartik, live site
Everything worked until I tryed out some themes, then returned to the original, Bartik.
Trying to 'Add content' sends: 'You have not created any content types yet. Go to the content type creation page to add a new content type.'
In Admin>Structure>Content types there is a full list of all my content types.
In Content list, the type of content is still displayed as 'basic page' (which is what I have used so far).
So, everything is there, only 'Add content' can't see it.