message: provide a user-friendly message indicating that the Kiali secret is missing and that all logins are prohibited until a secret is created.
diff: @@ -38,6 +38,9 @@ const loginState = (state: LoginState = INITIAL_LOGIN_STATE, action: KialiAppAct
  let message = 'Error connecting to Kiali';
  if (action.payload.error.request.status === 401) {
  message = 'Unauthorized. Error in username or password';
  + } else if (action.payload.error.request.status === 520) {
  + message =
  + 'The Kiali secret is missing. Users are prohibited from accessing Kiali until an administrator creates a valid secret and restarts Kiali. Please refer to the Kiali documentation for more details.';
  }
  return Object.assign({}, INITIAL_LOGIN_STATE, {
  error: true,
  