WP-admin login

Probably I misunderstood the purpose of the plugin. I need something to manage the access to my site, and I changed (in the settings) to login

email only

What I wanted is that, after accessing the (free) home page, the user is forced to enter email and password to proceed. What happened is that the wp-admin login was affected, and I could not any longer enter via wp-login with my regular username (not email) and pwd. In my opinion, this is not correct: the administrator wp-login should NOT be affected by the plugin settings. I was forced to define another wp-admin user to access the dashboard and correct the issue.