This is often a mistake:
you do not have permission, override mode. (server or .htaccess file).
also set the file - .htaccess.
Incorrect server address (https or http).
check where the link goes, e.g. "https://sample.de/home".
Ok, I'll checked the htaccess file... could have done that before. When updating from PHP 7.2. to 7.3 this file was obviously overwritten by the web server.