Views module shows no taxonomy anymore

Hi all,

Since yesterday the views module does not show any taxonomy terms anymore when I choose a content of a type with taxonomy terms. Normally it worked just well and there used to pop up a field where I could choose a term.
Like:

Add a new view --> Show "content" --> of type "Article" --> Here would normally pop up a taxonomy term field, this is gone.

Luckily the views I made before are still these terms included.

How to fix this?

Thanks.