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 – RESOLVED

22/01/2026 15:38:00 AM

NHSmail Reference: INC46730962

Microsoft Reference: EX1221076

Issue Status: RESOLVED

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.

Final Update: 26/01/2026 09:26:00 AM – Microsoft has confirmed that the fix deployment has completed successfully and that the issue has been fully resolved.

Scope of impact: Impact is specific to some users attempting to delete email messages after running the QUIT command using POP3 connection method.

Root cause: A package version conflict introduced a regression that causes the POP3 QUIT command to fail after a DELE operation.

Next Steps: Microsoft are reviewing their package provisioning procedures to help prevent similar problems in the future.