WP_FAIL2BAN_BLOCK_USERNAME_LOGIN

Force login with email address/prevent login with username.

Default setting: disabled

Added in version 4.3.0.

Forces users to log in using their email address instead of their username. This provides an alternative to blocking user enumeration when using themes with author profile pages.

Example: Force email login

/**
 * Force login with email address/prevent login with username.
 */
define('WP_FAIL2BAN_BLOCK_USERNAME_LOGIN', true);

Important

You should define this in wp-config.php even if you are using the Premium flavour of WPf2b.