Resolving a blocked sending IP with Office365 requires a multi-faceted approach. The first step is to understand that Office365 and Outlook.com have distinct blocking and delisting processes and to use the sender.office.com portal for delisting, which may require account verification and detailed information about sending practices. Proactive monitoring of your sending reputation using tools like Google Postmaster Tools helps identify issues early. Key to maintaining a good sending reputation is implementing strong email authentication (SPF, DKIM, DMARC), properly configuring reverse DNS (PTR records), maintaining a clean email list, warming up new IPs gradually, and keeping sending volumes consistent. Also, regularly checking blocklists and ensuring high engagement metrics contribute to a positive reputation. Transparency with postmasters and a willingness to provide detailed information about sending policies and problem resolution are crucial. Furthermore, using a dedicated IP can provide more control over sending reputation and setting up feedback loops allows for prompt identification and correction of issues reported by recipients.
10 marketer opinions
To resolve a blocked sending IP with Office365, several key strategies emerge. It's important to first follow the delisting process via sender.office.com, which may take a few days. Maintaining a clean email list by removing inactive subscribers is crucial. Authentication using SPF, DKIM, and DMARC records, along with a properly configured reverse DNS (PTR record), enhance email reputation. Warming up a new IP address with gradually increasing sending volumes is recommended, as well as maintaining consistent sending patterns. Monitoring blocklists and addressing any listings is essential. Switching to a dedicated IP address provides more control over sending reputation. High engagement metrics and setting up feedback loops are vital. Transparency regarding sending practices is needed to demonstrate trustworthiness and resolve issues.
Marketer view
Email marketer from Reddit shares that checking if your IP address is on any public blocklists (like Spamhaus or Spamcop) is important. If you are listed, take steps to get delisted according to their procedures.
26 Nov 2021 - Reddit
Marketer view
Email marketer from Gmass explains setting up feedback loops with email providers allows you to receive notifications when users mark your emails as spam, so you can identify and address any issues.
31 May 2021 - Gmass
4 expert opinions
To resolve a blocked sending IP with Office365, it's essential to understand that Office365's blocking and delisting processes are distinct from Outlook.com. Transparency is crucial when communicating with postmasters, including providing detailed information about sending practices and addressing issues that led to the block. Ensuring SPF, DKIM, and DMARC records are correctly configured to authenticate emails is also vital.
Expert view
Expert from Word to the Wise explains that sender.office.com may require you to verify your IP address and provide detailed information about your sending practices and policies, emphasizing the need for transparency and a clear explanation of how you are resolving the issues that led to the block.
11 Jan 2024 - Word to the Wise
Expert view
Expert from Email Geeks shares that the reverse DNS is cybersmart.com, which isn't the most suspicious but the redirect to cybersmart.co.uk was removed. Suggests transparency for postmasters when trying to get unblocked.
25 Feb 2025 - Email Geeks
4 technical articles
Resolving a blocked sending IP with Office365 involves utilizing the sender.office.com delisting portal, where you may need to create an account and verify sending practices. Proactively monitoring your sending reputation using tools like Google Postmaster Tools can help identify and address issues before they lead to blocking. Implementing and correctly configuring SPF and DMARC records is crucial for verifying email authenticity, preventing spoofing and protecting your domain from phishing attacks. Using a 'p=reject' DMARC policy instructs email providers like Office 365 to strictly block unauthenticated emails.
Technical article
Documentation from DMARC.org explains that implementing DMARC policy is critical for protecting your domain from email spoofing and phishing attacks. It provides instructions to email providers (like Office 365) on how to handle emails that fail SPF and DKIM checks. Using a 'p=reject' policy will result in strict blocking of all emails that do not pass authentication.
18 Mar 2024 - DMARC.org
Technical article
Documentation from Google Postmaster Tools recommends using their tools to monitor your sending reputation and identify potential issues that may lead to blocking by email providers like Office 365. This can help you proactively address problems before they impact deliverability.
30 Aug 2024 - Google Postmaster Tools
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