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Unplanned Outage: Some users are unable to send or receive email messages in Exchange Online

Last Updated:
2021-04-22 23:02:14
Event:
2021-04-22 15:50:00
Status:
Closed
Brief Description:
Some users are unable to send or receive email messages within Exchange Online. CIT is working with Microsoft to resolve the issue.
User Impact:
Users may be unable to send or receive email messages within the Exchange Online service.
Workaround:
There is no workaround for this issue
Current Status:
We have monitored the environment and confirmed that the queued emails have processed as expected.
Services Affected:
Email and Calendar
Subsites Affected:
GuestIDs
Full Description:
Some users are unable to send or receive email messages within Exchange Online. Some users may receive the error message '451 4.3.2 Temporary server error. Please try again later ATTR1' if they attempted to email an impacted organization. CIT is working with Microsoft to resolve the issue.
CIT TDX ID:
328761



Timeline of Changes

Description Current Status Date Time
Some users are unable to send or receive email messages within Exchange Online. Some users may receive the error message '451 4.3.2 Temporary server error. Please try again later ATTR1' if they attempted to email an impacted organization. CIT is working with Microsoft to resolve the issue. We have monitored the environment and confirmed that the queued emails have processed as expected. 2021-04-22 23:02:14
Some users are unable to send or receive email messages within Exchange Online. Some users may receive the error message '451 4.3.2 Temporary server error. Please try again later ATTR1' if they attempted to email an impacted organization. CIT is working with Microsoft to resolve the issue. Our preliminary investigation has determined impact is being caused by a load balancing configuration issue. This occurs when a call to validate inbound mail is received. This call is being duplicated, creating a spike in utilization. We're working to restore the underlying database infrastructure to remediate impact. 2021-04-22 16:22:20