Error Rest-API

WP ist installed in subdirectory /bs21 and redirection works fine. The website is now switched to https://l-boxx.com/ – and redirection is not working:
Error: NetworkError when attempting to fetch resource.`

>> home and siteurl different: ERROR

THX for any ideas or support

Marco

`Plugin: 5.2.3 4.2
WordPress: 5.9 (single)
PHP: 8.0.15
Browser: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:97.0) Gecko/20100101 Firefox/97.0
JavaScript: https://l-boxx.com/bs21/wp-content/plugins/redirection/redirection.js?ver=5.2.3-cb109e7c800603ff2d5cc098451320be
REST API: https://l-boxx.com/wp-json/
Query: ?page=redirection.php&sub=support

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