Browse to https://kagi.com/assistant while not logged-in (or a private/incognito window or new cookie jar). See this 404 page:
It reproduces in Firefox (desktop Linux), Chromium (desktop Linux), Firefox (Android), and Vanadium (Android).
This could instead guide the user toward success. When browsing to https://kagi.com/search while logged-out, you get a 302 redirect to https://kagi.com/signin, which is a much more helpful page. A similar redirect here would fix this issue.
