What do I have to do to fix that?
No valid storage adapters means you’re playing in a privacy mode, or otherwise have cookies turned off. The game doesn’t use cookies, it used local storage, but the cookies setting controls local storage too in modern browsers. The game requires local storage access to run.
If you didn’t turn off cookies, it could be an extension doing it. There are also some so-called “secure” browsers, like Brave, that simply don’t grant web pages access to local storage. So those aren’t supported at all.