Printing Layout: Overview Map blank

Hi All,

I saw different Posts about this, but didn' find a solution that works: I have a Print Template, using just VS Printing, not Printing Engine. I've selected my own Overwiev Map with the Germany Boundaries and activated the Hellgrau Grundkarte. It's a really simple Overview Map
 

I then selected this Map in my Template, with these Parameters
 

But it's still printing a blank Overview Map, without Boudaries

What's I'm doing wrong?

Thanks for any Help!