[Flow] Problems with Authentication

[Mario]

I am just migrating an Flow3 1.1 App to Flow 2.0 and by testing my login I get the following inside my Security_Development.log:

"Authentication failed: "The security context contained no tokens which could be authenticated." #1258721059"

My Configuration/Settings.yaml looks like this:

TYPO3:
  Flow:
    session:
      inactivityTimeout: 86400
    i18n:
      defaultLocale: 'de'
  security:
    enable: TRUE
    authentication:
      authenticationStrategy: allTokens
      providers:
        DefaultProvider:
          provider: PersistedUsernamePasswordProvider
          entryPoint: 'WebRedirect'
          entryPointOptions:
            routeValues:
              '@package': 'Xxx.Xxx'
              '@controller': 'Login'
              '@action': 'index'
              '@format': 'html'

To login I use the example form of "The Definitive Guide".

Any idea what is wrong here?