Microsoft 365 Alert – Service Degradation – Exchange Online – Users may be unable to delete email messages after running the QUIT command when POP3 connection method is used – ONGOING

22/01/2026 15:38:00 AM

NHSmail Reference: INC46730962

Microsoft Reference: EX1221076

Issue Status: ONGOING

Issue Description: Users may be unable to delete email messages after running the QUIT command when POP3 connection method is used.

More info: Specifically, POP3 users can read and download their email messages, but any messages they delete may not actually be removed, because the session fails to close properly. If a message is deleted on Exchange Online using the DELE command, the POP3 QUIT command may fail, preventing the session from closing cleanly and causing messages marked for deletion to remain in the mailbox. If the user is not using POP3, they are not impacted.

Current Update: 22/01/2026 15:38:00 AM – Microsoft have identified an issue where a recent update introduced a conflict that prevents the POP3 QUIT command from completing after a message is deleted. We’ve validated a fix in our test environment and initiated a deployment to affected users. The deployment is progressing through a gradual rollout and we expect full completion within the next 24 to 48 hours.

Scope of impact: This issue may have impacted any prompts users sent to Copilot or services that leverage Copilot responses, such as Microsoft Teams Facilitator.

Root cause: A high utilization event temporarily caused parts of our infrastructure to become unbalanced when attempting to handle traffic load, which resulted in delays.

Next steps: Our review of the high resource utilization event continues so we can improve our automation’s response time to such events and reduce delays or avoid the issue altogether.