Ένα μήνυμα για κάθε αποτυχημένη σύνδεση

<?php

// Change the message to your own words or language if you like.
add_filter(
	'login_errors',
	static function ( $error ) {
		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Only reads which form this is.
		$action = isset( $_REQUEST['action'] ) ? sanitize_key( wp_unslash( $_REQUEST['action'] ) ) : 'login';
		if ( 'login' !== $action ) {
			return $error; // Lost password and registration keep their messages.
		}
		return '<strong>' . esc_html__( 'Error:' ) . '</strong> ' . esc_html( 'Wrong username or password.' );
	}
);