Paste the following code in your theme’s functions.php:

add_action( 'wp_logout', 'auto_redirect_external_after_logout');
function auto_redirect_external_after_logout(){
  wp_redirect( 'URL OF REDIRECTION' );
  exit();
}

 

Source: https://wordpress.stackexchange.com/questions/15633/how-can-i-redirect-user-after-entering-wrong-password