Why can't I watch a movie

Why is it not possible to watch the movie, yet? It's three days after release and the store says, the relase was three days ago - but I can't watch it (preorderet in May 2019)...

Please - just do make it possible to watch that movie.

connect to network.. that's how it works..

Correct, and just to add a reference point,
this is covered on this page, here. It specifically says:

• Purchases from Movies & TV are not downloaded to your console but are streamed over the Internet to your console or other Movies & TV-compatible devices. For more information, see Microsoft
  Store: Movies & TV.

Now, what you CAN do with that, is sign up for
Movies Anywhere. Then all of your eligible Microsoft Movies & TV content will sync over with Movies Anywhere and then you could use a service that DOES allow you to download and watch the movie offline, though through a very cursory search does not look
like there is an option on Xbox One? Vudu is a Movies Anywhere app, though I have never used it to see if you can download titles for offline play.

Thanks for adding the extra info.

I would point out though that Movies Anywhere is only available in the US.

Correct, and just to add a reference point,
this is covered on this page, here. It specifically says:

• Purchases from Movies & TV are not downloaded to your console but are streamed over the Internet to your console or other Movies & TV-compatible devices. For more information, see Microsoft
  Store: Movies & TV.

Now, what you CAN do with that, is sign up for
Movies Anywhere. Then all of your eligible Microsoft Movies & TV content will sync over with Movies Anywhere and then you could use a service that DOES allow you to download and watch the movie offline, though through a very cursory search does not look
like there is an option on Xbox One? Vudu is a Movies Anywhere app, though I have never used it to see if you can download titles for offline play.

To start the movies you must be online