Authenticator blocks password app

In the past I acquired an account with LastPass password authenticator. I used it on my iPhone, iPad en Windows computer. Recently I was busy trying to get access to a car rental website, which asked for authentication. Somehow or other I activated the Authenticator facility which now is proscribed as method of login help. See image below. This is a facility without the passwords of LastPass. How can I go back to the old situation?