Index page not showing

My index page is not showing. So when I go to www.my-domain.com, I get a 404 page not found error, however, when I go to www.my-domain.com/my-page.html, it works.

I'm not sure whether something went wrong when I tried to install (and uninstall) a language extension (I forgot which one). I now have the Changelanguage extension installed.

For some reason, the issue is already resolved.

Usually, this "issue" relies on a missing "Language fallback" setting.