Why are my emails to henmail.se going to spam even with engaged users?
Michael Ko
Co-founder & CEO, Suped
Published 11 Jun 2025
Updated 18 Aug 2025
6 min read
It can be incredibly frustrating when your emails land in the spam folder, especially when you're diligently sending to your most engaged users. The situation becomes even more perplexing when the recipient domain is as specific as henmail.se. Despite having a list of active 30-day clickers, a 0% open rate and no bounces of any type from a small audience of around 160 recipients strongly suggest a significant filtering issue at the recipient's mail server.
This scenario indicates that your emails are likely being blocked or heavily filtered before they even reach the inboxes of your engaged subscribers. Understanding the nuances of how smaller, potentially personal, mail servers handle incoming mail is crucial for diagnosing and resolving such deliverability challenges.
Understanding unique domain challenges
Unlike major providers such as Gmail or Outlook, smaller or personal domains often have less sophisticated spam filtering systems. They might rely on simpler rules, or even specific manual configurations that can be highly sensitive. These mail servers might lack the advanced algorithms that major providers use to analyze sender reputation and engagement signals over time.
The domain henmail.se appears to be a smaller, possibly personal or business domain, which could be less robustly managed than a large corporate email system. Small domains might also be hosted on shared IP addresses that are inadvertently impacted by other senders, leading to a poorer reputation for the entire IP range. This can result in legitimate emails being caught in a broader net of spam filtering. You can investigate general reasons why your emails are going to spam by common causes.
Furthermore, a small domain might have a very low threshold for what it considers suspicious. Even a slight anomaly in sending patterns, content, or authentication can trigger their filters, especially if they haven't seen much mail from your sending IP or domain before. This is particularly true if the domain owner has configured strict personal spam settings. An in-depth guide to email blocklists can shed more light on how these lists operate and impact deliverability.
Beyond engagement: Technical foundations
While your users at henmail.se may be engaged, technical misconfigurations can still prevent your emails from reaching them. Proper email authentication, including SPF, DKIM, and DMARC, is the first line of defense against emails being marked as spam or blocklisted. Even if your authentication records appear to be in place, subtle issues can lead to failures that go unnoticed without proper monitoring.
Essential authentication checks
SPF record: Ensure all sending IPs and third-party senders are authorized. An SPF TempError can still occur even with a seemingly correct record.
DKIM signatures: Verify that your DKIM signatures are correctly generated and align with your sending domain. Issues like a DKIM body hash mismatch can cause delivery problems.
DMARC policy: Implement a DMARC policy, even if it's set to p=none, to receive reports on authentication failures. These reports can provide critical insights into why emails are not reaching the inbox.
Even with small send volumes, your sender IP and domain reputation are paramount. A poor reputation can lead to immediate rejection or spam folder placement. This can be influenced by previous sending habits, or even the reputation of other senders sharing your IP address, if you're not using a dedicated IP. Check if your domain has been blacklisted (or blocklisted) on any major blocklists, as some smaller domains may use these lists for filtering.
Content, list hygiene, and negative signals
The content of your emails plays a significant role in deliverability. Even with engaged users, certain elements can trigger spam filters. This includes overly promotional language, excessive images, broken links, or suspicious formatting. Spam filters are constantly evolving, and what might have worked last month could be flagged today. Review your email content for anything that might appear suspicious to an automated filter.
Common content issues
Spammy keywords: Overuse of terms commonly found in unsolicited mail. Tools exist to test your email content for spamminess.
Broken links or tracking pixels: These can raise red flags for filters.
Poor HTML: Messy or non-standard HTML can be misinterpreted.
Solutions and best practices
A/B test content: Send variations to a small segment of your list to identify trigger words or phrases.
Use a clear call to action: Ensure your intentions are transparent.
Optimize for mobile: Many users view emails on mobile devices, so ensure your layout is responsive and clean.
Even with engaged users, a small percentage of negative engagement can disproportionately impact deliverability to smaller domains. If even a few of your 160 engaged henmail.se users mark your email as spam, it sends a strong signal to that domain's mail server that your emails are unwanted. This can lead to future emails being filtered more aggressively.
It's also worth considering that spam traps or honeypots could be present, even if your list is highly engaged. These are inactive or invalid email addresses used by mailbox providers to identify senders with poor list hygiene. Sending to just one can severely damage your sender reputation with that specific provider.
Monitoring and advanced diagnosis
Since henmail.se is a small domain, it's unlikely to provide a postmaster site or detailed feedback loops like Google Postmaster Tools. This lack of transparency makes direct diagnosis challenging. However, you can still monitor your overall domain and IP reputation using general tools and blocklist checkers to catch broader issues.
Consider the possibility of a shared IP address being on a blocklist (or blacklist). Even if your domain is clean, a blocklist on your IP can affect all emails sent from it. Using a blocklist monitoring service can help you identify and react quickly if your IP address or domain gets listed. Remember, what happens when your IP gets blocklisted can severely impact your deliverability across all recipients.
It might also be beneficial to reach out directly to one or two of your most engaged henmail.se contacts through an alternative communication channel (if appropriate and non-intrusive) to inquire if they are receiving your emails in their spam folder. Their feedback could provide unique insights into specific filtering rules they might have in place. The website henmail.se seems to be tied to a person on Twitter, which could offer a direct point of contact for inquiries if public outreach is an option.
Views from the trenches
Best practices
Always maintain pristine list hygiene, removing inactive or invalid addresses, even for engaged segments.
Monitor your DMARC reports closely for authentication failures, which can signal underlying deliverability issues.
Segment your audience further, starting with super-engaged users before gradually expanding volume to new domains.
Common pitfalls
Assuming engagement alone guarantees inbox placement, especially with smaller or niche mail providers.
Ignoring the impact of shared IP addresses on sender reputation if you're not using a dedicated IP.
Not thoroughly testing email content for spam triggers across various email clients and filters.
Expert tips
Implement and monitor all three email authentication protocols: SPF, DKIM, and DMARC.
Warm up new sending IPs or domains gradually, even for small lists, to build trust with mail servers.
Encourage recipients to whitelist your email address and add you to their contacts.
Marketer view
Marketer from Email Geeks says checking the domain showed it was valid for emailing, but the organization was unknown to them, making it hard to reach out directly.
2021-03-08 - Email Geeks
Marketer view
Marketer from Email Geeks says they guessed that henmail.se is a small personal or possibly business domain.
2021-03-08 - Email Geeks
Next steps for inbox success
Resolving deliverability issues to specific domains like henmail.se requires a multi-faceted approach, combining robust technical setup with careful content and list management. The fact that you're sending to engaged users is a strong positive signal, but it doesn't negate the need for impeccable email hygiene and authentication.
Focus on ensuring all your email authentication records are perfectly configured and continuously monitored. Pay close attention to your sender reputation, not just generally, but specifically for smaller mailbox providers that might have stricter filtering. By addressing these potential blind spots, you can significantly improve your chances of reaching the inbox, even on challenging domains.
Gmail or 
Outlook, smaller or personal domains often have less sophisticated spam filtering systems. They might rely on simpler rules, or even specific manual configurations that can be highly sensitive. These mail servers might lack the advanced algorithms that major providers use to analyze sender reputation and engagement signals over time.
