Other Reasons Why Valid Emails Bounce or Go to Spam

All of us have had the following situation at least once: you wait for a confirmation email for your recent purchase only to find it hours later in your Spam folder. If that sounds familiar, you are not alone: emails can bounce or land in spam for different reasons. Oftentimes, it has nothing to do with the sender's reputation.

What can be the reasons?

1. Restrictions are imposed on the IP address of the sender’s server by email service providers or spam filters. If the sender’s IP address was previously used to send emails that were classified as spam, there’s a high likelihood that emails sent from that IP address in the future will also be classified as spam – regardless of the actual content.

   Other contributing factors here can be:

   • Spam words in email subject or body
   • Writing in all caps
   • Spelling or grammar mistakes
   • Excessive use of unusual fonts, emojis, exclamation marks, etc.
   • Suspicious links in the message body
   • Images used are too big or there are too many of them
   • Email attachments of all kinds
2. Sometimes, a recipient can manually mark your email as spam. This often happens when the content of your emails is not interesting to subscribers, lacks personalization or sounds too generic. To avoid this, try asking your subscribers, such as via a survey, what topics they would like to read about and craft your campaigns accordingly.
3. IP addresses or email addresses might not be sufficiently warmed up for mass mailings. What does that mean? IP warming is basically a gradual increase of email volumes sent from it, which allows you to slowly build a positive sender reputation. If you start mass-mailing from a new IP address, it can raise suspicions among mail server providers. Besides, when thousands of emails are sent from a new site, it raises a legitimate question: how did a new site acquire so many subscribers?
4. You simply send too many emails. Excessive enthusiasm for sending emails might bring the opposite results to what you intended: instead of increased open rates, you will be added to spam. Aim for no more than two emails per week – this is a sweet spot between being attentive and not overly intrusive.
5. Lack of consistency. When it comes to sending emails, one of the best things you can do to avoid triggering spam filters is being consistent. Flooding your recipients’ mailboxes during one time period, while being inactive during others is the wrong approach. Instead, make a schedule with the optimal times and numbers of emails, and try sticking to it.
6. Sender domain authentication is not configured. This means that your email address was not verified and authorized to send emails from a specific domain. By undergoing verification, you demonstrate to recipients and providers that your emails are not from impostors, which makes them more trustworthy. It also helps verify that the domain belongs to a legitimate mail transfer agent (MTA) authorized to transmit emails, further reducing spam concerns.
7. Incorrect configuration of SPF, DKIM, and DMARC records when setting up the sender’s email. SPF, DKIM, and DMARC are email authentication methods that ensure emails are sent from authorized servers and help verify the sender's domain. By correctly setting up these protocols, you reduce the risk of emails being marked as spam, improve deliverability, and protect the sender's domain reputation at the same time.
8. The double opt-in option is not configured. When a user signs up for an email list, they get an email with a link to confirm subscription. When they click on the link, it counts as the second time they confirmed their willingness to receive emails, with the first one being when they subscribed in the first place. Double opt-in allows only interested users who are engaged with the company’s content to be added to the database. Having a relevant and active database helps reduce the number of complaints about your mailings and reduces spam concerns.
9. Use of free public domains. This is another reason for higher spam concerns and deliverability issues. Free domains are typically unable to set up proper SPF and DKIM records because they do not have the control required for it. As a result, emails from such domains often fail DMARC validation checks, which are critical for establishing the legitimacy of the sender.

You can always check your sender’s reputation for free here: https://senderscore.org/