Language set from different domains not working

The site is hosted with Westhost.
alexandraepple.de is set as alias and points to the folder where alexandraepple.com files are (public_html).

I use 2 languages: English as default and German.
The language switcher is on the footer menu.
When I set URL modifications to “The language is set from the directory name in pretty permalinks” everything works correctly.
When I set it to “The language is set from different domains”, the German version of home page redirects to the English one.
There are other translated pages that behave the same:
https://alexandraepple.com/bodyjoy (English) -> https://alexandraepple.de/bodyjoy (German)

There are more pages translated and none of them is working in German, but unlike the homepage, these German pages show this error message in Chrome:
“This page isn’t working
alexandraepple.de redirected you too many times.
Try clearing your cookies.
ERR_TOO_MANY_REDIRECTS”
Examples of pages that give me this error:
https://alexandraepple.com/blog/(English) -> https://alexandraepple.de/blog-g/(German)
https://alexandraepple.com/connect/ (English) -> https://alexandraepple.de/kontakt/ (German)
https://alexandraepple.com/work-with-methai-massage/ (English) -> https://alexandraepple.de/thai/

Please help me solve this.
Thank you.

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