Pages not showing anymore - 1 Closed group suddenly only plane text

I have 2 problems that occured together

  1. When I click the link pages I get a blank page ../pages/all can somebody tell me what to do here?
  2. I have one closed group that suddenly has only text and links and no theme anymore everything else is just fine but this group's homepage has only text on a white page, the blogposts, filespage, etc are all ok just the homepage isn't.

Thanks for any help