SychO Hey, thank you for the fast answer. Sadly, when I do this, this completely breaks Flarum's images and throws more errors. It has worked with the www. in the config.php before, too, so this should not be the error I guess.
Edit: I found the error. The .htaccess of the website root enforces to use www. - the standard .htaccess of Flarum doesn't. If you change it to lead to www. in this case, too it is working as entended again. Thank you!
