With increasing frequency I am receiving email delivery failure notices related to emails sent from my business web site. When a customer places an order, an email facsimile of the order is sent to me and a copy is sent to the customer. During the last year or so I’ve noticed an increase in emails that were undeliverable. The notices cited reason 550 which was defined sometimes as being on a blocked list and sometimes as “unknown host.”
To send a copy of the order form to our customer I use a few lines of visual basic, as follows:
Dim MM As New MailMessage()
MM.From = New MailAddress("email@example.com")
'next line takes email address entered
'by customer on the order form and adds to CC
MM.Body = "---------------------------------"
'Body of email created here
MM.Priority = MailPriority.Normal
My little company sends very few advertising emails and only to existing customers. However, bounced order-copy emails that totaled about one per month a year ago now are almost one a day. I was wondering if I could send the order form copy email using a different coding technique which would reduce the likelihood of being mistakenly considered spam? Or is this sending technique violating some sort of spam detection algorithm?