Why is Microsoft blocking my IP address even after warming up?

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).

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.

Email marketer from Stack Overflow suggests that even after a warm-up, Microsoft might block you if users are marking your emails as spam. High complaint rates are a major red flag for Microsoft's filtering systems.

Email marketer from SendGrid Support explains that Microsoft sometimes employs aggressive throttling. Monitor feedback loops for complaints, check your Sender Score regularly, and keep the content relevant and engaging.

Email marketer from Microsoft Support shares that even after warming up, your IP may still be blocked if your IP or sending domain has a poor reputation. This is often due to factors like sending unwanted email, low engagement rates, or being listed on blocklists.

Email marketer from Reddit suggests that, even with a warmed-up IP, poor content or misleading subject lines can cause users to mark emails as spam. This can negatively impact your sender reputation and lead to blocks.

Email marketer from Email Marketing Forum suggests that the quality of your email list is important. Even with a warmed-up IP, sending to old, unengaged, or purchased lists can lead to high bounce rates and spam complaints, causing blocks.

Email marketer from ReturnPath explains that sudden increases in sending volume after the warm-up period can trigger spam filters. Continue to gradually increase volume, even after the initial warm-up phase.

Email marketer from GlockApps suggests that regularly test your emails to identify potential deliverability issues. Testing helps identify potential issues that might cause filters to block your emails.

Email marketer from Litmus suggests that sending to spam traps can lead to blocks. Even with a warmed-up IP, hitting spam traps indicates list hygiene issues that will negatively impact your reputation.

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.

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.

Expert from Word to the Wise shares that even after warming up, Microsoft may block your IP if your sender reputation is poor, content is irrelevant or spammy, and subscribers aren't actively engaged with your emails, indicating deeper trust issues beyond the initial IP warm-up.

Expert from Email Geeks explains that there is no way to warm your way out of a block for sending non opt-in email and Microsoft is actively blocking this mail because it’s spam.

Expert from Email Geeks shares that even with single opt-in, if Microsoft blocked the IP and before the sender got a week into warmup (only sending 400 emails) they were blocked again, it means Microsoft simply does not think their subscribers want that mail and something is wrong that goes deeper than warmup.

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.

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.

Documentation from RFC explains that after the initial IP warmup, it's important to maintain a consistent sending volume and sending patterns. Drastic changes in volume can trigger filters even if the IP was initially warmed up properly.

Documentation from Outlook.com Postmaster describes how ensuring proper authentication (SPF, DKIM, DMARC) is essential. Even with a warmed-up IP, missing or incorrect authentication can lead to deliverability issues and blocks.