hotmail
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, here’s what’s happening, I think, based on what some smart folks have shared with me.All of those domains have an MX record that points to outlook-com.olc.protection.outlook.com. And when you look up the IP addresses for that server mentioned in the MX record, what do you get? Well, when I do it from here, I get just two IPs: 104.47.58.33 and 104.47.55.33.But other folks showed me examples where they were receiving 25+ IP addresses in response. I can’t reproduce it, so I don’t know if it’s geo-specific, intermittent, or if overall, the whole thing has been addressed. I suspect some combination of all of that. But anyway, I’m told that when the results
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’s a link to a KBXSCORE report I’ve run, showing the failure.While hotmail.com is affected, the outlook.com domain doesn’t appear troubled — my test sends from an outlook.com from address seem to pass SPF. (Microsoft has many other domains; I’ve only checked these two.)Looking at the SPF records for hotmail.com, here’s what I see:hotmail.com descriptive text “v=spf1 include:spf-a.outlook.com include:spf-b.outlook.com ip4:157.55.9.128/25 include:spf-a.hotmail.com include:_spf-ssg-b.microsoft.com include:_spf-ssg-c.microsoft.com -all”outlook.com descriptive text “v=spf1 include:spf-a.outlook.com include:spf-b.outlook.com ip4:157.55.9.128/25 include:spf-a.hotmail.com include:_spf-ssg-b.microsoft.com include:_spf-ssg-c.microsoft.com include:spf.protection.outlook.com ~all”The hotmail.com SPF record is missing “include:spf.protection.outlook.com” — which is present in the outlook.com SPF record. And I see it present in a cached copy of Hotmail’s SPF record that I collected last month. So, I suspect that to be
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 relatively common to have deliverability issues at Microsoft only, and nowhere else. You are not alone.Not only can Microsoft often be “quicker on the trigger” when it comes to blocking, but also, resolution of deliverability issues can take longer here versus other mailbox providers. It’s not always clear what triggers spam folder placement or blocking — but like with so many other mailbox providers, the best thing you can do to minimize deliverability risk is to send truly wanted mail. No purchased lists, no email appends, no ten year old lists you found in the back of a filing cabinet. Sending engaging, wanted, recognized mail, is going to be your
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 blocked those messages or relegated them to the Junk Folder.I wasn’t able to confirm this myself; my personal and test Outlook.com addresses are too well protected from public view; meaning they’re not on any common spam lists. I’ve updated my website contact info to use an outlook.com account, so I’m sure I’ll start getting spam there soon. Maybe I’ll be able to observe this for myself. (Hey, that’s aliversonchicago@outlook.com, for all the spambots out there.)This could be causing a unique scenario or two. Not only are bad guys perhaps scrambling to send as much garbage as they can before the spam filter loophole is corrected, but for email sending platforms
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 trying to send it over IPv6 and send the mail to any IPv4 MX record instead, and then your queues will drain successfully.What domains are affected? Likely all domains I’ve listed here as handled by Microsoft, and only if you send over IPv6, and only if the recipient domain is a Microsoft-hosted domain that has an MX record with a hostname that maps to an IPv6 address.If you’re sending mail using an ESP or CRM platform, you’re probably not affected by this. Big mail sending platforms, especially US-based ones, almost exclusively use IPv4 IP addresses, not IPv6.Why is this affecting mail over IPv6 only? Nothing has been confirmed, but I
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.Where it says 10 complaints at 4:30 pm and 18 complaints at 4:37 pm, I think that means that eight complaints came in between 4:30 and 4:37. Might that be useful for folks looking to better identify which sends at which time are generating the most complaints?Note: It appears that the date/time in that comments field is when the complaint occurred, not when the campaign was sent. I’ve seen at least one example where that complaint date in the comments is a few days after the campaign send date. I suspect that could cause a bit of confusion.[ H/T: Mawutor Amesawu and Jennifer Nespola Lantz ]