Outage in SMTP2GO
Delays sending to Microsoft-hosted domains
Resolved MinorIncident Report
Summary AI Generated
SMTP2GO experienced a 24.2-hour service disruption affecting email delivery to Microsoft-hosted domains (hotmail.com, outlook.com, live.com, etc.), with emails showing as "Processed" but failing delivery with "451 4.7.650" error responses. The issue was caused by a global Microsoft-wide problem that affected multiple email service providers, not a fault with SMTP2GO's systems. The incident was resolved once Microsoft fixed the underlying issue on their end.
We are currently aware of a global issue affecting emails sent to Microsoft-hosted domains (such as hotmail.com, outlook.com, live.com, etc.). Emails affected will show as "Processed" on the "Reports > Activity" page, and delivery attempts encounter "451 4.7.650……….." responses. This is a Microsoft-wide issue affecting multiple SMTP providers/ESPs, and we are monitoring it closely as they actively work on a fix. Thanks for your patience.
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Latest Updates ( sorted recent to last )
RESOLVED
about 2 months ago - at 02/27/2026 03:08AM
This incident has been resolved.
MONITORING
about 2 months ago - at 02/26/2026 03:01AM
We are currently aware of a global issue affecting emails sent to Microsoft-hosted domains (such as hotmail.com, outlook.com, live.com, etc.). Emails affected will show as "Processed" on the "Reports > Activity" page, and delivery attempts encounter "451 4.7.650……….." responses. This is a Microsoft-wide issue affecting multiple SMTP providers/ESPs, and we are monitoring it closely as they actively work on a fix. Thanks for your patience.
Latest SMTP2GO outages
Inbound Server Issue - 10 days ago
Investigating Email Processing Delays (AU Region) - 25 days ago
Network Connectivity Issues - about 2 months ago
Activity Page Headers - 2 months ago
Connectivity issues for "mail-au.smtp2go.com" - 3 months ago
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