Incorrect verification

function __construct() {
    	add_action( 'init', array( $this, 'postResgiter' ) );
		if ( get_option( 'mo_enable_firebase_auth' ) == 1 ) {
			remove_filter( 'authenticate', 'wp_authenticate_username_password', 20, 3 );
			 remove_filter( 'authenticate', 'wp_authenticate_email_password', 20, 3 );
			add_filter( 'authenticate', array( $this, 'mo_firebase_auth' ), 0, 3 );
		}
    }

In the above code you are removing both WP authentication types when Firebase auth is enabled, but this doesn’t account for the option of BOTH WP and Firebase you have in the plugin.

You are removing all options to WP authenticate if Firebase is on.

For the time being I commented out the remove_filter for the option I want to keep, but please account for BOTH in the next update.