Microsoft 365 Alert – Service Degradation – Exchange Online – Users may be unable to send or receive Exchange Online email messages through the native iOS Mail app using EAS – RESOLVED

Announcements Arpan Das

20/11/2025 09:37:00 AM

NHSmail Reference: INC46686617

Microsoft Reference: EX1185322

Issue Status: RESOLVED

Issue Description: Users may be unable to send or receive Exchange Online email messages through the native iOS Mail app using EAS.

More info: The impacted users can authenticate without issue, but they receive the error “Cannot Get Mail. The connection to the server failed.” when trying to refresh email messages in the Mail app.

Final Update: 21/11/2025 08:57:00 AM – Microsoft have confirmed with affected users that disabling the offending change has remediated impact. This confirms that a recent HTTP3 configuration change for the QUIC feature in the Exchange Online client access path resulted in impact.

Scope of impact: Impact may occur for some users, where they can’t send or receive Exchange Online email messages through the native iOS Mail app using EAS.

Next Steps: Microsoft are reviewing their QUIC feature change validation process to improve the detection and prevention of similar HTTP3 configuration issues in the future.