C# code:

public IHttpActionResult SubmitForm([FromBody]string json)
{
    var purchaseOrder = JsonConvert.DeserializeObject<PurchaseOrder>(json, defaultSettings);
    using (var connection = new SqlConnection(ConfigurationManager.ConnectionStrings["myDatabase"].ConnectionString))
    {
        try
        {
            // submit the info into the database
        }
        catch(SqlException e)
        {
            logger.error(connection , "Exception saving purchase order", e);
            return InternalServerError();
        }
    }
    Task.Run( () =>
        {
            using (var connection = new SqlConnection(ConfigurationManager.ConnectionStrings["myDatabase"].ConnectionString))
            {
                try
                {
                    // send email
                    logger.debug(connection , "Sent email");
                }
                catch(Exception e)
                {
                    logger.error(connection , "Exception sending email", e);
                }
            }
        });
    return Ok();
}