WordPress SMS API integration without plugin

Question

I think this is the error. The last variable $msg is incorrectly inserted. Here is the corrected code.

function mysite_woocommerce_order_status_processing( $order_id ) {

    $mobile="123456";

    $url="****/api.php?username=******&password=1234&source=UPDATE&dmobile=".$mobile."&message="".$msg.""";

    $response = wp_remote_get( $url );

    //print_r($response);

}

add_action( 'woocommerce_order_status_processing','mysite_woocommerce_order_status_processing' );