We often receive emails from customers who claim they received high bounce rate reports from their Email Service Provider (ESP), even after validating the email addresses on their lists with our service. This often occurs with customers who have not mailed to a specific list in a long time, or are new to an ESP. These customers will see messages from their ESP similar to "554 Reject by behavior spam" or "554 Spam violation." While it may seem like certain email addresses are labeled with these messages because they are invalid email addresses, that is actually not the case.
These messages are a result of Spam Filtering. After sending your message to your desired recipients, even though they may be opt-in contacts, you may still be marked as spam. There are many reasons this might happen and we're featuring two of those reasons below. In next week's follow-up post, we will have additional resources and information for you.
It's important to note that the reasons for these messages are not related to whether or not the email addresses you're sending to are valid. If we've validated a list of emails for you, and you mail to the correctly identified "verified" group, then it's very likely that your bounce rate does not correspond to the validity of the emails on your list, but rather the content of your message.
Spam filtering is a complex topic, so if you need hands-on help, we recommend retaining a deliverability consultant or using many of the available online resources. We are good friends with many industry folks, so if you'd like to reach out to an organization in particular, we're happy to introduce you to a specific contact there!
MailChimp has a variety of helpful resources for this, and should be able to point you in the right direction. Other good resources, if you want to go the self-taught route (which is certainly doable!) are articles from Return Path, Word to the Wise, and Spamhaus. All of that being said, here are some of the many possibilities your message is being filtered as spam:
Other resources that could help you with email marketing best practices (and where we have many contacts!) are the Email Experience Council and Inbox Group.