API REST : /login should return true if auth is disable

I'm developing an Android app which uses the REST API. In order to check whether the configuration entered by the user is correct, I use the "/login" method.
When authentication is enabled, if it returns `{success: true}`, the configuration is right, if it returns `{success: false}` the username and password don't match, else, the url is wrong.
When authentication is disabled, it returns `false`. So we can't know if the user forgot to set its username and password or if the config is right.
That's why I think that this method should always return `true` if authentication is disabled.