Localhost and <mydomain> login behavior different

Help
1

I newly installed directus with template into my localhost (Mac mini)
npx directus-template-cli@latest init

I ensured it can login via default admin, then use cloudflare to make my site accessible via net.

With the same credential I hit if access via my domain. Localhost still login without issue. Any clue?

{
  "errors": [
    {
      "message": "Invalid user credentials.",
      "extensions": {
        "code": "INVALID_CREDENTIALS"
      }
    }
  ]
}