C＃使用System.Net.Mail发送大量电子邮件

We have an ASP.NET MVC application that sends a number of reports via e-mail to clients each month. Each e-mail attaches a monthly statement. Currently we have around 70 clients but this will hopefully increase over time. We have been seeing issues that a number of e-mails are not getting sent. We use the System.Net.Mail API.We have an ASP.NET MVC application that sends a