Summary
Even after warming up an IP address, Microsoft may continue to block it due to underlying issues impacting sender reputation, list hygiene, engagement, and technical configurations. Sending non-opt-in email guarantees blocks, while low subscriber engagement signals to Microsoft that recipients don't want the mail. High complaint rates, hitting spam traps, being on blocklists, and inconsistent sending volume contribute to poor reputation. Proper email authentication (SPF, DKIM, DMARC) is crucial. On shared IPs, others' sending practices affect deliverability. Monitoring SNDS, participating in FBL, testing emails, and ensuring relevant content are key to mitigating these issues.
Key findings
- Non-Opt-in = Blocked: Sending non-opt-in email will always result in blocks from Microsoft.
- Reputation Matters: Poor sender reputation stemming from various issues (complaints, spam traps, etc.) can lead to blocking even after warming up.
- Engagement is Key: Low subscriber engagement signals to Microsoft that recipients don't want the mail.
- List Quality Matters: Poor list hygiene (old, unengaged, purchased lists) leads to high bounce rates and spam complaints.
- Technical Configurations: Missing or incorrect email authentication (SPF, DKIM, DMARC) causes deliverability issues.
- Monitoring is Essential: Monitoring SNDS and feedback loops helps identify and address problems.
- Sending Volume is Crucial: Inconsistent sending volume can trigger spam filters, blocking email
Key considerations
- Obtain Explicit Consent: Ensure that all recipients have explicitly opted-in to receive your emails.
- Clean Your Lists Regularly: Maintain good list hygiene by removing unengaged subscribers.
- Create Relevant Content: Produce engaging, relevant email content to encourage subscriber interaction.
- Proper Authentication: Implement SPF, DKIM, and DMARC to authenticate your emails.
- Monitor SNDS: Regularly monitor your IP's health using Microsoft's SNDS.
- Participate in FBL: Use Microsoft's Feedback Loop (FBL) to remove complainers from your list.
- Test Emails: Test your emails for deliverability issues before sending.
- Consistent Volume: Maintain a consistent sending volume to avoid triggering spam filters.
What email marketers say
10 marketer opinions
Even after warming up an IP address, Microsoft may continue to block it due to various factors impacting sender reputation. These factors include poor list quality (old, unengaged, purchased lists), high complaint rates, sending unwanted email, misleading content, hitting spam traps, being listed on blocklists, and issues related to shared IP pools. Aggressive throttling by Microsoft and sudden increases in sending volume can also lead to blocks. Monitoring feedback loops, maintaining consistent sending patterns, and regularly testing emails are crucial for maintaining deliverability.
Key opinions
- Poor Reputation: Even after IP warm-up, a poor sender reputation can lead to continued blocking. This is influenced by factors like spam complaints and low engagement.
- List Quality: Sending to old, unengaged, or purchased lists can cause high bounce rates and spam complaints, leading to blocks.
- Content Issues: Poor or misleading content in emails can cause users to mark them as spam, negatively impacting sender reputation and leading to blocks.
- Blocklist Status: Being listed on a DNS blocklist or Realtime Blackhole List (RBL) can result in continued blocking, even after IP warm-up.
- Aggressive Throttling: Microsoft may employ aggressive throttling, which can lead to emails being blocked or delayed.
- Sudden Volume Increases: Sudden increases in sending volume after the warm-up period can trigger spam filters and cause blocks.
- Shared IP Impact: On shared IP pools, the actions of other senders can affect your deliverability, leading to blocks.
- Spam Traps: Sending emails to spam traps negatively impacts sender reputation and can lead to blocks.
Key considerations
- Monitor Reputation: Regularly monitor your sender reputation to identify and address any factors that may be negatively impacting it.
- Clean Email Lists: Maintain clean and engaged email lists by removing old, unengaged, and purchased contacts.
- Optimize Content: Ensure email content is relevant, engaging, and avoids misleading subject lines to reduce spam complaints.
- Check Blocklist Status: Regularly check if your IP address is listed on any blocklists and take steps to remove it if necessary.
- Monitor Feedback Loops: Monitor feedback loops for complaints and adjust sending practices accordingly.
- Maintain Volume Consistency: Avoid sudden increases in sending volume after the warm-up period and maintain consistent sending patterns.
- Test Emails Regularly: Regularly test emails to identify potential deliverability issues before sending to a large audience.
Marketer view
Email marketer from Email Vendor Reputation FAQ shares that your IP may be on a blocklist. After warming up check if your IP address has been mistakenly listed on any DNS blocklists or Realtime Blackhole Lists (RBLs).
9 Oct 2024 - Email Vendor Reputation FAQ
Marketer view
Email marketer from Mailjet shares that if you're on a shared IP, the actions of other senders can impact your deliverability. Even with a proper warm-up, a neighbor's poor sending practices can lead to your IP being blocked.
22 Aug 2023 - Mailjet
What the experts say
5 expert opinions
Even after warming up an IP address, Microsoft may continue blocking it due to underlying issues that affect sender reputation and engagement. Sending non-opt-in email will always result in blocks. Low subscriber engagement, stemming from irrelevant content or poor list hygiene, signals to Microsoft that recipients don't want the mail, leading to continued blocks. Overcoming these blocks requires addressing the root causes of poor reputation, such as improving list quality, ensuring opt-in practices, and creating engaging content.
Key opinions
- Non Opt-in Email: Sending non opt-in email will always result in blocks from Microsoft.
- Deeper Issues Persist: Continued blocking after warming up indicates deeper issues like poor list hygiene, high complaint rates, or technical configuration problems.
- Lack of Subscriber Engagement: If subscribers are not actively engaged with emails or the content is irrelevant, Microsoft may block the IP.
- Reputation Impact: Poor sender reputation stemming from list quality, low engagement, or irrelevant content can result in Microsoft blocking even after warming up.
Key considerations
- Ensure Opt-in Practices: Verify that you are only sending mail to recipients who have explicitly opted in to receive it.
- Improve List Hygiene: Regularly clean your email lists to remove unengaged subscribers and reduce complaint rates.
- Relevance and Engagement: Create compelling, relevant email content that encourages subscriber engagement to signal to Microsoft that your emails are wanted.
- Investigate Technical Issues: Thoroughly examine your technical setup to identify and fix any configuration problems that may be contributing to deliverability issues.
Expert view
Expert from Email Geeks explains that there are no blocks against certain types of content really. 'Content' (and domain and IP) are really just the identifiers that the reputation is hung off of. The fact that he couldn’t get 400 messages before the blocks were back up says that the recipients REALLY didn’t want that mail.
26 Oct 2023 - Email Geeks
Expert view
Expert from Spam Resource explains that continued blocking after warming up often indicates deeper issues like poor list hygiene, high complaint rates, or technical configuration problems that require thorough investigation beyond just the IP warm-up process.
11 Feb 2022 - Spam Resource
What the documentation says
4 technical articles
Even after warming up an IP address, Microsoft may still block it due to factors detectable through their monitoring tools and adherence to email standards. Specifically, low engagement, high spam trap hits, inconsistent sending volume, and lacking proper email authentication (SPF, DKIM, DMARC) can lead to continued blocks. Participating in Microsoft's Feedback Loop (FBL) to remove subscribers who mark emails as spam is essential for maintaining list hygiene and reducing the risk of blocks.
Key findings
- SNDS Monitoring: Microsoft's Sender Network Data Services (SNDS) helps monitor IP health; low engagement, high spam trap hits, and complaint rates can lead to blocks after warmup.
- Authentication: Proper email authentication (SPF, DKIM, DMARC) is crucial; missing or incorrect authentication can cause deliverability issues and blocks even with a warmed-up IP.
- Sending Volume: Maintaining consistent sending volume and patterns is important after warmup; drastic changes can trigger spam filters.
- Feedback Loop: Participating in Microsoft's Feedback Loop (FBL) identifies subscribers who mark emails as spam, allowing removal to improve list hygiene.
Key considerations
- Monitor SNDS: Use Microsoft's SNDS to regularly monitor IP health and address any issues identified.
- Implement Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) is correctly configured to improve deliverability.
- Maintain Sending Patterns: Maintain consistent sending volume and avoid drastic changes in sending patterns after the initial warm-up.
- Participate in FBL: Utilize Microsoft's Feedback Loop (FBL) to identify and remove subscribers who mark emails as spam.
Technical article
Documentation from Microsoft details that participating in Microsoft's Feedback Loop (FBL) helps identify subscribers who mark your emails as spam. Removing these subscribers improves list hygiene and reduces the risk of blocks.
24 May 2022 - Microsoft
Technical article
Documentation from Microsoft SNDS explains that using the Sender Network Data Services (SNDS) allows you to monitor the health of your IP address as seen by Microsoft. Low complaint rates, high trap hits and low engagement after a warmup period can lead to continued blocking.
23 Jun 2023 - Microsoft SNDS
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