Showing posts with the label hotmail

Wait, what is Microsoft SNDS? (for 2026)

Every time I post about changes to Microsoft SNDS, somebody always asks, “What, what is Microsoft SNDS? How do I use it?” And so, to be proactive this time around, allow me to link to this wonderful introductory overview and explainer from fellow deliverability expert, Iterable’s Rob Schneider , as he explains how to use the IP reputation data provided by Microsoft SNDS to help improve your …
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New Microsoft Sender Requirements: Link Roundup

By now, you've probably heard: Microsoft has officially joined the club. Following in the footsteps of Google and Yahoo, Microsoft has announced new requirements for high-volume and bulk email senders targeting their consumer domains (the biggest ones being Outlook.com, Hot…

2025 MAGY Sender Compliance Guide

Here it is, the 2025 Spam Resource MAGY (Microsoft, Apple, Google, Yahoo) Bulk Sender Compliance Guide. This contains almost everything you need to know (I think? I hope?) about how to comply with modern email bulk sender requirements as mandated by the largest consumer mailbox…

Microsoft Joins the Club: Top four B2C MBPs now require email auth

Deliverability is ever-evolving. Another day, another major mailbox provider raising the bar for bulk email senders. This time it's Microsoft tightening things up for their Outlook.com consumer mailboxes (outlook.com, hotmail.com, and live.com), effectively aligning their p…

Navigating Microsoft OLC Spam Folder Placement

Microsoft’s Outlook.com or OLC (Outlook Consumer) email platform, the mailbox provider formerly known as Hotmail, can be a tricky one when it comes to managing and mitigating deliverability issues. There’s not always a clear and easy path to solve for spam folder/junk email fol…

Microsoft OLC/Hotmail Domains List (Updated for 2025)

Here it is, the first episode of "Fun with Data" for 2025. Today, I present to you a link to a downloadable list containing the top Microsoft Outlook.com (Microsoft OLC / Hotmail) email domains . Why would you need this? Maybe you run some certain mail server ( MTA -…

Microsoft: Decoding hidden spam-related headers

Did you know that Microsoft Outlook.com and O365 emails include special headers that break down the spam filtering results for email messages? These headers can help you decode the Spam Confidence Level (SCL), Phish Confidence Level (PCL) and Bulk Confidence Level (BCL) values …

MBP Spotlight: outlook.com

Who hosts what mail? MBP Spotlight is the new series here at Spam Resource where I’ll share ranking data for the top mailbox providers (including B2B!) based on where they fall in the top ten million domains. Some entries might have more info, some entries might have less, de…

Microsoft errors: 5.4.4 (unable to route: no mail hosts for domain)

When sending to Microsoft OLC (Outlook Consumer - i.e. hotmail.com, outlook.com, msn.com, live.com, etc.) domains, are you seeing this bounce message? Microsoft: 5.4.4 (unable to route: no mail hosts for domain) If you're seeing that error message, or something similar, her…

Hotmail.com SPF issue on August 18th

Looks like Microsoft has run into email authentication issues today. Specifically, the domain hotmail.com appears to have a broken SPF record wherein messages sent by Hotmail/Outlook.com/Microsoft OLC using a hotmail.com from address aren't passing SPF authentication. Here&…

Microsoft: Body hash did not verify error

If you're seeing intermittent DKIM authentication failures at Microsoft domains (outlook.com, hotmail.com, etc.) -- meaning you're seeing "dkim=fail (body hash did not verify)" instead of "dkim=pass (signature was verified)" in your "Authenticat…

ISP Deliverability Guide: Microsoft OLC (Updated for 2023)

Successful inbox delivery to Microsoft consumer mailboxes (referred to as Outlook.com, Hotmail.com, or Microsoft "OLC") can be tricky. Any deliverability consultant will tell you that Microsoft is often the quickest to block or junk your mail, and that it is relativel…

Outlook spam filters fall down, go boom

Mashable's Tim Marcin and others are reporting that a failure in Microsoft's spam filtering has resulted in Outlook.com (Hotmail) users receiving a bunch of spam in their inbox unexpectedly. Meaning, something broke -- a something that would have previously either blo…

Problems sending to Microsoft over IPv6? You're not alone

Multiple folks over on the Mailop list are reporting that Microsoft OLC (Outlook.com/Hotmail/etc)'s IPv6 inbound mail servers are deferring inbound mail delivery attempts with "451 4.7.500 Server busy. Please try again later" errors. The fix seems to be to stop …

New info in Microsoft SNDS

Check it out! It looks like Microsoft has updated SNDS to provide a bit more info than they provided previously. In the "Comments" column, they're now including snapshot counts of spam complaints received for that IP address at various points throughout the day. W…

SNDS shows no data from June 17th - June 21st

It's not just you! Microsoft's Sender Network Data Services  reputation portal seems to have stopped updating. The last date with IP address level reputation information is June 16th. Try selecting any date after that, and you'll get "No data for specified IPs …

Requesting pre-emptive accommodation from Microsoft

If you are new to your sending IP addresses -- meaning you're going through IP warming, you are likely to find that Microsoft OLC (Hotmail and related domains ) can be quick to block your sending IP address. My guides  here  and here talk through the general process for re…

AMP: The next big thing? Not at Outlook.com

Once upon a time I asked if AMP dynamic content functionality was going to be " the next big thing " as far as email is concerned. Google's got support for it in Gmail , and Verizon announced future support for it in Yahoo Mail , but it looks like Microsoft is wal…

Help! I'm blocked at Microsoft! What do I do?

Keep in mind that Microsoft has two separate mail systems: OLC (Outlook Consumer) which you might call Hotmail, and corporate mail hosting, the mail systems associated with their Office 365 service. The two systems have separate processes with regard to requesting to be unblock…

Outlook.com has tabs now, too?

What? This seems new. Brad Gurley talks about this over on his Delivery Counts blog . He says the tabs that show up include "Focused Inbox, Microsoft’s 'Priority Inbox' clone, along with Promotions, Social, and Newsletters." Find more details and screenshots h…