When you send an email, you expect it to reach the recipient’s inbox and to be read by the person. Otherwise, you just wasted your time and resources. For one email, it is a minimal loss. For companies sending large email campaigns, the loss is thousands of dollars if nobody reads their emails and engages with them.
Therefore, ensuring Inbox delivery for their email communications is an important part of the email sending workflow in every organization regardless of their customer base size and email types.
If you’re sending emails from a personal or business domain and they’re consistently landing in the Spam or Junk folder, the problem is usually a combination of various factors, in particular:
Inbox providers analyze thousands of email messages sent from your domain and/or IP and calculate your reputation score that determines whether you are a trusted sender and whether your emails are wanted by the recipients.
Inbox providers use different signals to measure the reputation where the most important ones are:
Therefore, the sender reputation score doesn’t stay the same. It can change based on your sending habits and user actions affecting your deliverability.
Email authentication uses three protocols, which guarantee the sender’s legitimacy and the email’s integrity:
Inbox providers made it a requirement to have properly configured SPF, DKIM, and DMARC records for a sending domain. Failing to configure email authentication results in email rejections or Spam placements.
Email content can contribute to filtering. But this doesn't mean that using one particular "spam word" automatically sends an email to Spam. Modern filtering stepped far away from simple keyword matching.
Common warning signs triggering spam filters include:
When you find out that your marketing or transactional emails start going to Spam, address this issue early to avoid serious problems in the future. As email placement is determined by various factors, there are a lot of things to check.
If the issues that make the emails go to Spam stay unclear, follow these recommendations to verify your email setup:
The quality of your subscriber list is the prerequisite of your email marketing success. A valid and active audience helps you build a good sender reputation by opening, reading, and clicking your emails.
Best email list management practices include:
Verify the quality of email addresses to make sure you are sending messages to people who requested them and who are really interested in the content you have to share.
Even the best domain configuration may be broken during a DNS update or change. Email authentication failures can cause the emails filtered out to Spam. Thus, verify your domain DNS setup to ensure that:
Although a MX record doesn’t authenticate the domain, some servers may check it performing an additional step to verify the legitimacy of the sender’s domain.
The best way to verify all the domain’s DNS records is to use a TXT record checker like Dmarkoff. The tool provides free checkers that instantly return a detailed report about DNS records found for a domain. This way, it is possible to quickly validate a SPF, DKIM, DMARC, and MX record published for your sending domain.
A real-time domain TXT record checker will return all TXT records associated with third-party services.
Dmarkoff's free TXT checker lists the TXT records published for a domain.
Blacklisted domains and IP addresses can seriously impact deliverability. When an email is reported as spam, the source domain and IP can be added to different spam databases. Inbox providers can then use these signals to decide on email placement.
Use tools like MXToolbox to verify if your domain and a dedicated IP address appears blacklisted. Visit the blacklist’s site and find out how to de-list your domain or IP.
Some Inbox providers have the postmaster tools that allow senders to see the metrics collected by the provider based on the emails sent to its users.
For instance, Google Postmaster shows valuable metrics about the domain reputation, user reported spam rate, email authentication errors, and delivery failures.
Examine the domain metrics to see if any of these factors could negatively impact your deliverability.
Separate your transactional and marketing streams by different domains and IP addresses to avoid the domain reputation affecting the delivery of highly important transactional messages.
By using a different domain and possibly different dedicated IP address, you will ensure inbox delivery for urgent billing notifications, account registration or password resetting emails.
Examine your recent campaigns sent before the deliverability problem occurred to see what had changed. Did you suddenly increase your daily sending?
If you have already established sending patterns, don’t change them suddenly – this doesn’t stay unnoticed by filters. Increase sending volume slowly.
For a new domain, work on building a good reputation by starting with a small volume and ramping up gradually.
Inbox providers notice how the recipients react to your emails. Try to optimize your messages to give people a reason to interact with them. Consider these recommendations:
Check your email message for filter triggering elements such as:
Ensure your unsubscribe link can be easily found and is working. A one-click unsubscribe process is preferable. This allows you to avoid spam reports caused by the user’s inability to unsubscribe.
Postmaster tools only track the emails manually reported as spam by users. If an email goes to Spam directly, this stays overlooked unless the recipients tell you. Thus, you may never know what the real problem is.
Email spam testing helps you get a better picture about your reputation and deliverability. When doing spam testing, you emulate your normal email sending to receive the accurate results based on your domain reputation and email copy.
Spam testing tools like GlockApps make this easy – within a few minutes you get a detailed report including email placements across dozens of providers, spam scores with major spam filters, email authentication results, and content analysis.
Actionable recommendations will be included in each report.
A GlockApps report shows inbox, tabs and spam placement for each provider group.
A regular email testing allows you to catch the problem early. When a part of the emails sent to the same provider go to Spam, it is a signal for a careful examination of your email workflow and setup.
Discord sends account verification, password reset and notification emails from its own domain, so authentication for these messages is handled on Discord’s side. When they miss the inbox, the cause is usually on the receiving end: a strict filter on a work or school mailbox, a personal rule that moves unknown senders out of the inbox, or the recipient marking an earlier Discord email as spam. Verification links also expire, so a message that sat in Spam for a few days may no longer work.
This matters for server owners too. Many servers set a verification level that requires a verified email before new members can chat. A member whose verification email is stuck in Spam can’t take part, and often just leaves.
What members can do:
What server owners can do:
When your emails start landing in Spam, don’t just focus on your copy or Subject line. Check the entire email system including the domain configuration, reputation and authentication, your email list, and sending behaviour.
Email authentication helps receivers identify you, reputation and recipient interaction help determine if you are a trusted sender whose emails deserve to land in the Inboxes. A thorough audit, timely changes, and regular testing will ensure a high sender reputation and consistent Inbox delivery.
Julia Gulevich, Head of Customer Success at GlockApps and DMARKOFF | Email Deliverability Expert | 17+ Years in Email Marketing
Julia is the author of numerous articles on email deliverability and email authentication. She is known for her practical, data-driven approach that helps teams get more emails into inboxes and keep sending practices healthy.
Julia works closely with senders every day, providing technical support, troubleshooting deliverability issues, and making complex topics such as email infrastructure, authentication, and sender reputation easier to understand and deal with.
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