SMTP

Microsoft løste problemet i løbet af aftenen den 11/10 - Her er informationen på engelsk fra deres interne drift:

“Impact was specific to Simple Mail Transfer Protocol (SMTP). Most users would have experienced up to a 1-hour delay; however, in some cases, users may have encountered delays of up to 24 hours. Additionally, the email sender may have received a Non-Delivery Report (NDR) with a “451 4.7.500 Server busy” error message, and their attempt to retry delivery of the email may have been delivered up to 24 hours later.

Final status: We’ve completed our deployment of the change, which was a targeted reversion of the code issue causing impact. Users should now be experiencing mitigation, though some residual delays may still occur over the next hour as the change completes.

Scope of impact: Impact was specific to some users who were served through the affected infrastructure. The issue affected users Worldwide and only for a portion of IP addresses, therefore not all users experienced impact.

Start time: Monday, October 9, 2023 at 11:00 PM GMT+2
End time: Wednesday, October 11, 2023 at 7:00 PM GMT+2

Preliminary root cause: A recent service update that was applied to a section of infrastructure responsible for enforcing IP address anti-spam rules contained a code issue, which was resulting in the delays with SMTP email delivery.

Next Steps: - We’re further reviewing the recent update to understand how the code issue was introduced and to understand what prevented it from being detected in our update testing and validation procedures, which will allow us to prevent similar issues in future updates.”

Se evt. https://twitter.com/MSFT365Status/status/1712133426671698304