@msh This is very wrong. This does not look like a nginx directory listing. And Mastodon doesn't have anything that produces that output. It's listing files in the Mastodon root directory, not public! Thankfully .env.production can't be retrieved, but still. I would start suspecting foul play at this point. Some kind of malware or hack?
@msh Also check the public directory for an index.html file, it could hijack the / path like that if it existed, it's not supposed to exist. But check what/who created it, if that's what's happening.