Why are my emails landing in junk/spam folders?

The case

One of the most common challenges in email communication is having legitimate messages mistakenly classified as spam or junk by Email Service Providers (ESPs). If you’re confident that your emails are not spam yet they’re still being flagged as such, this article is designed to help you identify any underlying issues and improve your email deliverability.

Spam, often referred to as junk email, refers to unsolicited messages usually sent in bulk to a large number of recipients. To protect users from unwanted emails, Internet Service Providers (ISPs) and Email Service Providers (ESPs) employ sophisticated spam filters, algorithms, and historical data to evaluate and categorize incoming emails.

Each provider has its own set of criteria for determining whether an email is spam, which means that an email may pass through one provider’s filters but be flagged by another’s. Additionally, spam filters are constantly updated to keep pace with evolving spam tactics, so what was once considered acceptable might now be treated differently.

How to check if your emails are being sent to spam

If you suspect that your emails are landing in spam folders, there are several tools available that can help you confirm this and diagnose the issue on you end.

Email testing services like Mail Tester and Experte Spam Checker allow you to send a test email and receive an analysis of how your email is processed.

These services can identify issues such as spam classification before you send your emails to a broader audience.

Steps to resolve the issue

Since every ESP and ISP has its own criteria for classifying emails, pinpointing the exact reason your emails are being marked as spam can be challenging. However, there are several proactive steps you can take to improve your email deliverability, particularly by enhancing the reputation of your sending domain and IP address, as these factors are often used by email providers when classifying email traffic.

While Infobip cannot directly influence the filtering decisions of ESPs, we can offer recommendations to help improve your reputation and, as such, your deliverability.

Step 1: Follow deliverability best practices

Adhering to best practices is crucial in preventing your emails from being flagged as spam.

On this link, you can find a guide that covers key strategies for improving deliverability. These practices include maintaining a clean email list, using proper authentication methods, and crafting content that avoids common spam triggers.

Step 2: Gradual scaling

Start by sending emails to your most engaged recipients – those who have previously opened or clicked on your emails. This helps establish a positive sending reputation. Once you’ve built some momentum, gradually increase your sending volume each day. This controlled scaling improves deliverability and reduces the likelihood of you being flagged as a spammer.

Step 3: Avoid invalid recipients

Sending emails to invalid addresses or spam traps can severely damage your reputation and lead to your emails being marked as spam. To mitigate this risk, regularly clean your email list using an email validation service. These services can help you identify and remove invalid addresses before they harm your deliverability.

Information on Infobip’s validation solution can be found on this link.

Step 4: Reputation campaigns

A proactive approach to improving your reputation is to run campaigns targeted at your most engaged recipients. Encourage them to add your email address to their safe sender list and to move any of your emails from their spam/junk folders to their primary inbox. This boosts your reputation and also signals to ESPs that your emails are wanted by recipients.

Step 5: Contact Support

If you have followed the troubleshooting steps above and are still experiencing issues with your messages ending up in the spam folder, please don’t hesitate to contact our Support team for further assistance.

You can reach our Support team via [email protected].


Please provide the following information:

– Domain and campaign name: Specify the domain and the names of the campaigns that are experiencing issues.

– Traffic logs: Include examples of the affected email traffic, such as specific email addresses, dates, and times when the issues occurred.

– Campaign or template ID: Provide the ID of the campaign or email template that is being flagged as spam.