Summary
Emails landing in Office 365 spam folders can result from a multitude of interconnected factors, impacting IP reputation, email authentication, content, sender reputation, and list hygiene. Technical implementations like SPF, DKIM, and DMARC play a pivotal role in establishing trust. Maintaining a positive sender reputation through list hygiene and relevant content is crucial. Factors such as blocklisting, spam triggers, and individual recipient behavior also influence deliverability. Analyzing deliverability data, actively managing IP reputation, reviewing content, and aligning DMARC policies are key to resolving deliverability challenges.
Key findings
- Comprehensive Factors: Numerous factors can cause emails to land in Office 365 spam folders, requiring a holistic approach to troubleshooting.
- IP Reputation Impact: A poor IP address reputation, stemming from past spam activity or unestablished status, triggers spam filters and reduces deliverability.
- Authentication Deficiencies: Lack of proper SPF, DKIM, and DMARC email authentication exposes senders to increased spam filtering and compromised deliverability.
- Content as Trigger: Certain content types, formatting styles, and language usage serve as spam triggers, impacting deliverability.
- Sender Reputation Significance: Maintaining a positive sender reputation derived from complaint rates, engagement metrics, and bounce rates is vital to bypassing spam filters.
- List Hygiene Importance: Poor list hygiene contributes to bounces, degrades sender reputation, and increases the likelihood of emails landing in spam folders.
- Aggressive Filtering: Office 365 filters are known to be aggressive, requiring stringent email practices to avoid spam classifications.
Key considerations
- Analyze Deliverability Data: Consistently monitor and analyze bounce rates, complaint rates, and engagement metrics to determine the cause of deliverability issues.
- Actively Manage IP Reputation: Employ strategies for warming up new IPs, monitor IP reputation, and prevent sharing IPs with known spammers to avoid blocklisting.
- Review Email Content: Scrutinize email content and formatting for potential spam triggers to optimize deliverability.
- Employ List Hygiene: Clean email lists frequently by removing unengaged and invalid addresses to boost sender reputation.
- Align DMARC Policy: Ensure complete alignment of DMARC policies with email sending practices, especially when using third-party email services, to avoid blocked emails.
- Implement Authentication: Prioritize the correct implementation of SPF, DKIM, and DMARC records to ensure the authenticity of outgoing emails and build sender trust.
- Gather More Data: Avoid making assumptions about deliverability challenges and ensure access to comprehensive deliverability data.
What email marketers say
14 marketer opinions
Emails landing in Office 365 spam folders can stem from various factors. Analyzing bounce and complaint rates, ensuring proper email authentication (SPF, DKIM, DMARC), and maintaining a good sender reputation are crucial. Content that triggers spam filters (e.g., overly promotional language) and a poor IP address reputation can also contribute. Cleaning email lists, monitoring sending IP reputation, and aligning with DMARC policies are essential steps to improve deliverability. It's important to gather sufficient data before making assumptions, and consider that spam filtering can vary between recipients. Email design and being on blocklists are additional points to consider.
Key opinions
- Sender Reputation: A poor sender reputation, influenced by factors like bounce rates, complaint rates, and low engagement, significantly increases the likelihood of emails being filtered as spam.
- Email Authentication: Lack of proper email authentication (SPF, DKIM, DMARC) makes it difficult for Office 365 to verify the legitimacy of emails, leading to potential spam filtering.
- Content Triggers: Certain words, phrases, or email designs (e.g., overly promotional language, excessive use of images) can trigger spam filters and cause emails to be flagged as spam.
- List Hygiene: Sending emails to outdated or invalid email addresses increases bounce rates, damages sender reputation, and contributes to spam filtering.
- IP Reputation: A poor IP address reputation, potentially from sharing an IP with spammers or not properly warming up a new IP, can result in emails being filtered as spam.
Key considerations
- Data Analysis: Thoroughly analyze bounce rates, complaint rates, open rates, and other relevant metrics to identify the root causes of deliverability issues.
- Authentication Setup: Ensure that SPF, DKIM, and DMARC are properly configured to authenticate your emails and improve sender reputation.
- Content Review: Review email content for potential spam triggers, such as overly promotional language, ALL CAPS, and excessive exclamation points.
- List Cleaning: Regularly clean your email list to remove inactive or invalid email addresses and reduce bounce rates.
- IP Monitoring: Monitor your sending IP reputation using tools like Sender Score and take steps to warm up new IPs gradually.
- Blocklist Checks: Check if your domain or IP address is on any blocklists and take steps to get removed if necessary.
- DMARC Policy Alignment: If using third-party sending services, ensure they are properly aligned with your DMARC policy to prevent emails from being blocked.
- Individual vs. Global Filtering: Recognize that spam filtering can vary between recipients, so a single instance of an email going to spam may not indicate a widespread problem.
Marketer view
Marketer from Email Geeks highlights that just because emails are going to one person's spam folder, doesn't mean it is for everyone (and vice versa).
30 Sep 2023 - Email Geeks
Marketer view
Email marketer from Mailjet Blog shares that maintaining a good sender reputation is crucial for email deliverability. Factors that influence sender reputation include bounce rates, complaint rates, and engagement rates. They recommend consistently cleaning email lists, segmenting audiences, and sending relevant content to improve engagement and sender reputation, thus reducing the chances of emails landing in Office 365 spam folders.
12 Sep 2024 - Mailjet Blog
What the experts say
4 expert opinions
Emails are landing in Office 365 spam folders due to poor IP reputation, lack of proper email authentication (SPF, DKIM, DMARC), poor sender reputation (based on bounce rates, complaints, and engagement), and inadequate list hygiene. Maintaining a clean email list and ensuring a good IP and sender reputation are crucial for improving deliverability to the inbox.
Key opinions
- IP Reputation: A negative IP address reputation due to past spam activity or being a new, unestablished IP can cause Office 365 to flag emails as spam.
- Email Authentication: The absence or incorrect configuration of SPF, DKIM, and DMARC raises concerns about email authenticity, leading to potential spam filtering by Office 365.
- Sender Reputation: Damaged sender reputation, resulting from high bounce rates or recipient spam complaints, negatively affects email deliverability in Office 365.
- List Hygiene: Poor list hygiene, sending to inactive or invalid email addresses, significantly elevates bounce rates and harms sender reputation, contributing to spam classification.
Key considerations
- Improve IP Reputation: Take measures to improve your IP address reputation, such as warming up new IPs properly and avoiding spam-like sending patterns.
- Implement Authentication: Ensure that SPF, DKIM, and DMARC are correctly configured to authenticate your emails and verify your domain's legitimacy.
- Monitor Sender Reputation: Continuously monitor your sender reputation metrics (bounce rates, complaints, engagement) and address any issues promptly.
- Maintain List Hygiene: Regularly clean your email list to remove inactive or invalid addresses, minimizing bounce rates and enhancing sender reputation.
Expert view
Expert from Word to the Wise shares the importance of list hygiene. Regularly cleaning your email list to remove inactive or invalid email addresses is essential for maintaining a good sender reputation and preventing your emails from landing in the spam folder. Sending emails to nonexistent or abandoned email addresses will increase your bounce rate, which can negatively impact your deliverability.
2 Feb 2024 - Word to the Wise
Expert view
Expert from Spam Resource shares that the presence and correct configuration of email authentication protocols like SPF, DKIM, and DMARC are crucial. These protocols help verify that the emails are actually coming from the domain they claim to be, and a lack of them can raise red flags for Office 365.
22 Oct 2022 - Spam Resource
What the documentation says
6 technical articles
Emails land in Office 365 spam folders due to various factors, including sender IP or domain being blocklisted, content triggering spam filters, past recipient actions, and lack of or incorrect SPF, DKIM and DMARC configurations. SPF validates authorized mail servers, DKIM adds a digital signature to verify email authenticity, and DMARC builds on SPF and DKIM to prevent spoofing and phishing attacks.
Key findings
- Multiple Causes: Emails ending up in the Junk Email folder in Office 365 can be caused by a multitude of reasons.
- Blocklists: The sender's IP address or domain being present on a blocklist is a significant factor in emails being classified as spam.
- Spam Filtering: Content within the email that triggers spam filters is a contributing cause for emails ending up in the Junk Email folder.
- Past Recipient Actions: If recipients have marked similar emails as junk in the past, it can influence future email classification.
- SPF Importance: SPF records are essential for email authentication and verify authorized mail servers for your domain.
- DKIM Importance: DKIM adds a digital signature to outgoing emails to verify authenticity and prevent tampering.
- DMARC Importance: DMARC helps protect against spoofing, phishing, and other email-based attacks by building upon SPF and DKIM.
Key considerations
- Check Sender Reputation: Regularly monitor and maintain a positive sender reputation to avoid being flagged as spam.
- Ensure Email Authentication: Properly configure SPF, DKIM, and DMARC records to authenticate your emails and improve deliverability.
- Provide Clear Unsubscribe Options: Make it easy for recipients to unsubscribe from your emails to reduce spam complaints.
- Implement SPF: Implement SPF to validate outgoing email and authorize sending hosts, preventing spammers from forging sender addresses.
- Implement DKIM: Implement DKIM to permit the signing of messages by an organization and enable recipients to verify the messages.
Technical article
Documentation from RFC-6376 specifies that the DomainKeys Identified Mail (DKIM) defines a domain-level authentication framework for email. It permits signing of messages by an organization that controls the domain, which is then verified by message recipients. The signature travels with the email, allowing it to be verified at each hop along the mail path.
13 Oct 2022 - RFC-6376
Technical article
Documentation from Microsoft Learn explains that emails might end up in the Junk Email folder due to various reasons, including the sender's IP address or domain being on a blocklist, content triggering spam filters, or the recipient marking similar emails as junk in the past. They recommend checking sender reputation, ensuring proper email authentication (SPF, DKIM, DMARC), and providing clear unsubscribe options.
8 Mar 2022 - Microsoft Learn
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