Language code is missing in the url of just one page

Hello,
I would be very obliged if anyone had any suggestion!
My permalink settings are:

The language is set from the directory name in pretty permalinks
Hide URL language Information for Default language
Remove /language/ in Pretty permalinks
The front page url contains the language code instead of the page Name

I am using a static front page.

Default Language is German. Tranlated language is English.

The urls works fine for all pages but one. The language code is missing in the created url. This is why I get a missing Connection error when trying to open it from the menue. I tried to add the /en. But I get the same error. The only way to open that page is by preview.

I tried to deactivate the detection of the browser language. But without any success.
I tried to alter last part of the permalink, e.g. from “/contact-team” to “contact” and even changing the page title. But it had no effect.

Template is standard and the parent of this page is my english Homepage – as for all other pages. I tried to alter the partent page. But without any success.

I am lost here. As far as I can see all the settings are same as for all other pages. But for some reason there is a conflict with this page.

Do you have any suggestions what I could try to make that page available?

The page I need help with: [log in to see the link]