[FAQ]

Hey everyone,

I’m feeling pretty defeated right now. I’ve been putting a lot of effort into crafting our marketing emails, but it seems like they are consistently going straight to our subscribers’ spam or junk folders. Our open rates are terrible, and we’re getting feedback from the few people who do see them that they had to dig them out of spam.

What are the most common reasons this happens in 2025? Is it my subject lines? The content itself? Or is it something more technical that I’m missing? I just really need to know the key things to check and fix to improve our inbox placement.

Any advice would be great. Thanks.

[Jeff Bullas]

Having your emails land in the spam folder is a common and very frustrating problem. It is usually caused by a combination of factors related to your sender reputation, your technical setup, and the way your recipients engage with your content.

First, and most importantly, it could be due to a poor sender reputation. Internet Service Providers (ISPs) and inbox providers like Gmail and Outlook assign a reputation score to your sending domain and IP address. This score is damaged by things like having a high number of your emails marked as spam by recipients, high bounce rates from invalid email addresses, and low subscriber engagement. A poor reputation is a major red flag for spam filters.

Second, a very common technical reason is a lack of proper email authentication. You must have your SPF, DKIM, and DMARC records correctly set up for your domain. These are essentially your email’s digital passport. They prove to receiving mail servers that your emails are legitimate and that you are who you say you are, which helps to prevent spoofing and phishing. Many spam folders are filled with emails that have failed these authentication checks.

Third, low subscriber engagement is a powerful signal to inbox providers. If a large portion of your list never opens or clicks on your emails, it indicates that your content is not wanted. This is why it is so critical to regularly clean your email list and run re-engagement campaigns to remove inactive subscribers.

Fourth, you might be sending to a non-permission-based list. If you are emailing people who did not explicitly opt-in to receive your communications, such as from a purchased or scraped list, they are far more likely to mark your emails as spam. This is one of the quickest ways to destroy your sender reputation.

Fifth, while modern spam filters are very sophisticated, the content and formatting of your email can still be a factor. Using misleading subject lines, excessive capital letters or exclamation marks, including suspicious links or attachments, or using poorly formatted HTML code can all contribute to your email being flagged as spam.

And sixth, if you have recently started sending from a new domain, a sudden large increase in sending volume can appear as spammer behaviour. This is why it is essential to properly “warm up” a new sending domain by gradually increasing the volume of emails you send over time.

To begin troubleshooting, you should first use free online tools to check that your SPF, DKIM, and DMARC records are correctly set up. Then, analyse your list for engagement and be ruthless about cleaning out unengaged subscribers. These two areas often provide the solution.

Cheers,

Jeff

[Author]

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