CodeTwo incident
[Europe] Microsoft Exchange Online Protection issues
CodeTwo experienced a minor incident on May 10, 2021 affecting Mail flow and Mail flow and 1 more component, lasting 1h 8m. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- identified May 10, 2021, 08:42 AM UTC
We are currently monitoring an issue caused by a degraded performance of Microsoft Exchange Online Protection (EOP) which may lead to delays in email delivery for customers in Europe. This is a Microsoft 365 issue - not a CodeTwo issue. Do not take any action - emails with signatures should be sent to final recipients once this issue is fixed by Microsoft. The next update will be provided in 30 minutes or as events warrant.
- identified May 10, 2021, 09:13 AM UTC
We are continuing to monitor this issue. The impact seems to be low and only a subset of customers is affected. The next update will be provided in 30 minutes or as events warrant.
- resolved May 10, 2021, 09:51 AM UTC
This incident has been resolved.
- postmortem May 11, 2021, 01:51 PM UTC
Microsoft provided RCA regarding the issue under EX255429 in Microsoft 365 admin center. Here’s the summary: _**Title:** Some users may have been unable to send and receive external email messages within the Exchange Online service User_ _**Impact:** Users may have been unable to send and receive external email messages within the Exchange Online service._ _**Final status:** We've confirmed that cache has finished updating and the affected infrastructure has returned to service. After further monitoring, we've confirmed that this has resolved the issue._ _**Scope of impact:** Impact was specific to users who were served through the affected infrastructure located in Europe._ _**Start time:** Monday, May 10, 2021, 8:40 AM \(6:40 AM UTC\)_ _**End time:** Monday, May 10, 2021, 11:40 AM \(9:40 AM UTC\)_ _**Root cause:** A section of infrastructure, responsible for connecting email message attributes to end users, was not performing as expected due to the associated cache not fully updating._ _**Next steps:** - We're reviewing our caching infrastructure to find ways to prevent this problem from happening again. This is the final update for the event._