Yep, it's broken enough to be making the news. See https://www.cnbc.com/2026/01/22/microsoft-outlook-outage-email-issues.html and https://status.cloud.microsoft There's also "451 4.3.2 temporary server issue" deferrals as described there, but I am indeed seeing the same 550 5.1.2 Host unknown errors that you're mentioning.
Cheers, Al On Thu, Jan 22, 2026 at 3:54 PM L. Mark Stone via mailop <[email protected]> wrote: > > I know others have earlier yesterday and today reported DNS and SSL issues > with Microsoft, but we are now seeing lots of errors in our Zimbra MTA logs > like: > > <domain>-com.mail.protection.outlook.com[52.101.8.36] said: 451 4.3.2 > Temporary server error. Please try again later ATTR2 > [DS3PEPF000099D5.namprd04.prod.outlook.com 2026-01-22T20:45:56.009Z > 08DE596FAC061748] (in reply to MAIL FROM command)) > > > As well as errors like: > > (Host or domain name not found. Name service error for > name=<domain>-com.mail.protection.outlook.com type=A: Host not found, try > again) > > If I do a DNS lookup from my own workstation, I get: > > mstone@lms-macbookpro ~ % host <domain>-com.mail.protection.outlook.com > <domain>-com.mail.protection.outlook.com has address 52.101.41.58 > <domain>-com.mail.protection.outlook.com has address 52.101.194.15 > <domain>-com.mail.protection.outlook.com has address 52.101.8.34 > <domain>-com.mail.protection.outlook.com has address 52.101.42.16 > Host <domain>-com.mail.protection.outlook.com not found: 2(SERVFAIL) > Host <domain>-com.mail.protection.outlook.com not found: 2(SERVFAIL) > > Regards, > Mark > > -- > _________________________________________________________________ > L. Mark Stone, Founder > North America's Leading Zimbra VAR/BSP/Training Partner > For Companies With Mission-Critical Email Needs > Winner of the Zimbra Americas VAR Partner of the Year - Two Years Running ! > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop -- Al Iverson // 312-725-0130 // Chicago http://www.spamresource.com // Deliverability http://www.aliverson.com // All about me https://xnnd.com/calendar // Book my calendar _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
