Summary
Emails from Gmail/Gsuite accounts landing in Microsoft spam folders during replies is a multifaceted issue. While Gmail/Gsuite can be sources of spam, a primary factor is Microsoft's aggressive, idiosyncratic, and sometimes inaccurate filtering. This can stem from poor sender reputation (blocklisting, complaint rates), lack of authentication (SPF, DKIM, DMARC), email content triggering spam filters (including signatures/links), and even user-specific settings. Solutions involve robust authentication, monitoring/improving sender reputation, maintaining clean email lists, carefully reviewing content, and testing email placement.
Key findings
- MS Filtering Issues: Microsoft's filtering is often cited as aggressive, inaccurate, and unpredictable.
- Reputation Matters: Sender reputation, including blocklisting and complaint rates, significantly impacts deliverability.
- Authentication is Crucial: Lack of proper authentication (SPF, DKIM, DMARC) is a major cause of deliverability problems.
- Content Problems: Email content, including signatures and links, can trigger spam filters.
- Gmail/Gsuite as Source: Gmail and Gsuite are identified as significant sources of spam.
Key considerations
- Implement Authentication: Implement and maintain SPF, DKIM, and DMARC records correctly.
- Monitor Reputation: Monitor sender reputation and address any issues promptly.
- Clean Your Lists: Regularly clean your email lists to remove invalid and inactive addresses.
- Review Content Carefully: Review email content, including signatures, to avoid spam triggers.
- Test Email Placement: Use email placement testing tools to assess and improve deliverability to Microsoft accounts.
What email marketers say
10 marketer opinions
Emails from Gmail or Gsuite accounts landing in the spam folder of Microsoft accounts when replying to threads is a common deliverability issue. Several factors contribute to this, including Microsoft's potentially aggressive spam filters, sender reputation, email content, and authentication. Solutions involve improving sender reputation, ensuring proper email authentication (SPF, DKIM, DMARC), cleaning email lists, using natural language and avoiding spam trigger words in email content, and utilizing email placement testing tools.
Key opinions
- Aggressive MS Filters: Microsoft's spam filters can be overly aggressive and sometimes inaccurate.
- Sender Reputation: Poor sender reputation significantly impacts deliverability.
- Email Authentication: Lack of proper email authentication (SPF, DKIM, DMARC) increases the likelihood of emails being marked as spam.
- Content Triggers: Specific words, phrases, or email signatures can trigger spam filters.
- List Hygiene: Dirty or unmaintained email lists negatively affect deliverability.
Key considerations
- Implement Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) is set up correctly.
- Monitor Reputation: Regularly monitor and maintain a good sender reputation.
- Clean Email Lists: Maintain clean email lists by removing invalid or inactive addresses.
- Review Email Content: Carefully review email content to avoid spam trigger words and phrases.
- Test Email Placement: Use email placement testing tools to identify and resolve deliverability issues.
Marketer view
Email marketer from Sender explains that certain words and phrases can trigger spam filters and negatively impact deliverability. Suggests using more natural language, avoiding excessive use of exclamation points and capital letters, and providing value to subscribers in emails.
5 Dec 2022 - Sender
Marketer view
Email marketer from Reddit responds that Microsoft's spam filters are notoriously aggressive and sometimes inaccurate. They may be flagging emails due to various factors like content, sender reputation, or even the presence of links.
12 Feb 2022 - Reddit
What the experts say
3 expert opinions
Emails from Gmail or Gsuite accounts landing in spam when replying in threads with Microsoft accounts is often attributed to Microsoft's aggressive and sometimes inaccurate filtering practices. Factors contributing to this issue include the inherent challenges of filtering emails from Gmail/Gsuite (due to their high volume of spam), Microsoft's idiosyncratic filtering, and sender reputation problems like blocklisting or lack of proper authentication (SPF, DKIM, DMARC).
Key opinions
- MS Filtering: Microsoft's email filtering is aggressive, idiosyncratic, and can be inaccurate.
- Gmail Spam Source: Gmail and Google Workspace are significant sources of spam, making filtering challenging.
- Reputation Problems: Sender IP addresses on blocklists and poor sender reputation contribute to blocking.
- Authentication Issues: Lack of proper email authentication (SPF, DKIM, DMARC) leads to deliverability problems.
Key considerations
- Authentication: Implement and maintain proper email authentication (SPF, DKIM, DMARC).
- Reputation Monitoring: Monitor sender reputation and avoid being blacklisted.
- Filter Testing: Test emails with Microsoft accounts to understand how they're being filtered.
- Content Review: Review email content to ensure it does not trigger spam filters.
Expert view
Expert from Word to the Wise explains that Hotmail/Microsoft's filtering is often idiosyncratic and can be frustrating for senders. They mention possible reasons include IP reputation, content filtering, and user-specific settings, and they're known for being aggressive.
3 Sep 2024 - Word to the Wise
Expert view
Expert from Email Geeks explains that Gmail and Google Workspace are significant sources of spam. Says Microsoft filters are not very good. Also suggests that Microsoft is simultaneously more aggressive and less accurate in their filtering.
15 Sep 2021 - Email Geeks
What the documentation says
5 technical articles
Emails from Gmail or Gsuite ending up in Microsoft spam folders when replying in threads is influenced by sender reputation, email content, user settings (on the receiving end), and most importantly, email authentication. Proper implementation of SPF, DKIM, and DMARC is critical for both Gmail senders and all email senders in general. These protocols help verify the sender's identity and protect domains from spoofing and phishing attacks, significantly improving deliverability.
Key findings
- Sender Reputation: Sender reputation is a significant factor in email deliverability, as defined by Microsoft.
- Email Content: Email content and user settings can influence whether an email is marked as junk.
- Authentication Imperative: Proper email authentication (SPF, DKIM, DMARC) is essential to improve deliverability and prevent spoofing.
- DMARC Protection: DMARC helps protect domains from spoofing and phishing attacks.
- Google Guidelines: Google emphasizes sender guidelines, including authentication and easy unsubscribe options.
Key considerations
- Configure SPF: Create and configure SPF records to authorize sending servers for the domain.
- Implement DKIM: Implement DKIM to add a digital signature to outgoing emails.
- Deploy DMARC: Deploy DMARC to specify how recipient systems should handle emails that fail SPF and DKIM checks.
- Monitor DMARC Reports: Monitor DMARC reports to identify and address authentication issues.
- Check MS Settings: Advise recipients to add senders to the Safe Senders list in Microsoft Outlook.
Technical article
Documentation from Google Workspace Admin Help explains the sender guidelines for sending emails to Gmail accounts. It focuses on proper authentication (SPF, DKIM, DMARC), avoiding sending unwanted mail, and providing easy unsubscribe options for recipients.
9 Mar 2022 - Google
Technical article
Documentation from Microsoft Support explains that several factors can cause emails to be marked as junk, including sender reputation, email content, and user settings. Suggests adding senders to the Safe Senders list, checking junk email settings, and ensuring that email content does not trigger spam filters.
19 Aug 2021 - Microsoft
