Why is my Domain Being Flagged as Spam?

Have you had an issue with email deliverability or your domain being flagged as spam?

The industry standard for spam complaints is 0.1%.  This means if you send an email campaign to 10,000 recipients, just 10 of those people can report it as spam before your domain reputation will be impacted.  For most small and mid-sized businesses that are sending to even fewer recipients, just one reported message can quickly diminish your sending reputation.  


There are a number of considerations to factor in when addressing your domain reputation and improving your email deliverability for your business. In this article, you'll find the top factors that affect deliverability and how to maintain a good sending reputation for your domain.


What Affects Email Deliverability:

  • Engagement
    How often emails from your domain are opened and replied to, instead of simply deleted or marked as spam.

  • Volume
    The volume and frequency of emails you are sending out.

  • Unsubscribes
    The rate at which your recipients have unsubscribed from your emails.

  • Spam Complaints
    The number of recipients that reported your emails as spam.

  • Spam Traps
    Major Internet Service Providers (ISPs) set up accounts that look like normal email accounts, but are designed to target and eliminate email spam. If you send emails to to a spam trap account by mistake then you will get added to a block list.

  • Soft and Hard Bounces
    Soft bounces are usually temporary email delivery problems, but hard bounces happen when you've entered the wrong email address, the recipient's mailbox is full, or you have incorrect SPF and/or DKIM configured.  If you're seeing a large quantity of hard bounces, this may be due to improper public DNS settings.

  • Domain Authentication
    When mail systems receive a new message, they evaluate the message to determine if it's a spam or phishing email before passing legitimate emails on to the intended recipient.  One of the first things mail systems do is look for three published DNS records (SPF, DKIM, & DMARC) which contain information about what email systems may send mail using your company's email domain.  It's imperative that these three records are configured correctly and reviewed regularly for your emails to make it to their intended recipients.

  • Content
    Spam filters look at the email message itself for a variety of spam indicators, scanning your email's calls to action, subject lines, the number and type of attachments, and the message body. These filters are looking for indicators such as a sense of urgency, money-related (FREE! / Buy Now!) subject lines, odd punctuation or capitalization, pictures with embedded links, shortened URLs, adult-oriented language (expletives and/or language that is sexual in nature), links to known malicious websites, and more.

  • Mobile-friendly content
    Marketing emails have to be mobile friendly, or users will simply report it as spam to get it out of their feed.

  • IP reputation
    The behavior quality of the IP address you are sending from has an impact on deliverability. An example is that Office 365 has refined bulk email controls to prevent one Office 365 customer from ruining the IP reputation of all Office 365 IPs, since they are shared among many customers. If your sending domain is tied to directly to your own IP, only your email behavior should affect your domain's IP reputation.

  • Domain reputation
    The behavior quality associated with the email domain sending communications acts as your overall scorekeeper.  The more marks you receive in any of the above categories, the more your overall domain reputation will be affected.


Sending Bulk Emails Responsibly

If you are sending external emails to recipients by the thousands, bulk email best practices should be top of mind for email deliverability and reputation.

Your company's bulk email lists should be opt-in at a minimum, preferably double opt-in when possible for the best domain reputation protection.  Double opt-in means they signed up for the mailing list, and then you sent them a confirmation email and they approved it upon receipt, whereas only an initial signup action constitutes a single opt-in.

Following opt-in best practices, honoring opt-out requests, and adhering to CAN-SPAM laws are all necessities for sending bulk emails as a business of any size in any industry.