Resolved, according to Microsoft: Their service health telemetry reports indicate that the majority of users are no longer affected and additional remediation within the Microsoft-managed environment are not required.

For any remaining customers experiencing this issue, Microsoft's recommended actions are to click "continue" when prompted and navigate back to re-enter the password. Customers who aren't prompted but still experience impact should follow the steps in the following link: https://support.microsoft.com/en-us/office/reconnecting-your-microsoft-365-account-to-apple-mail-83df246e-34d2-4dbb-8e37-23a90c13e16e.

Locally, the incident began on March 3, 2025 when some CIT customers reported an issue accessing their M365 Exchange email messages on the iOS native mail application, Apple Mail, on their mobile devices. The vendor then reverted a standard service update that appeared to be the source of impact and thought the issue was mitigated on their end. 

However, after monitoring the affected infrastructure, the vendor determined the revert was not a viable mitigation strategy. They announced they would begin gathering "logs from a subset of affected users to refine our understanding of impact and formulate our remediation strategy."

On March 14, 2025, Microsoft reassessed the incident that interrupted Microsoft 365 Exchange email access in the native iOS mail app on mobile devices. The vendor said as affected users continue taking Microsoft's recommended actions, errors associated with the impact of that incident are reducing so additional remediation efforts within the Microsoft-managed environment are not necessary.

The Outlook app on iOS was not impacted. 

Vendor considers this issue resolved

Update: As of March 14, 2025, Microsoft has reassessed the incident that interrupted Microsoft 365 Exchange email access in the native iOS mail app on mobile devices. The vendor said as affected users continue taking Microsoft's recommended actions, errors associated with the impact of that incident are reducing so additional remediation efforts within the Microsoft-managed environment are not necessary.

Microsoft's recommended actions are to click "continue" when prompted and navigate back to re-enter the password. Customers who aren't prompted but still experience impact should follow the steps in the following link: https://support.microsoft.com/en-us/office/reconnecting-your-microsoft-365-account-to-apple-mail-83df246e-34d2-4dbb-8e37-23a90c13e16e.

 
Locally, the incident began on March 3, 2025 when some CIT customers reported an issue accessing their M365 Exchange email messages on the iOS native mail application, Apple Mail, on their mobile devices. The vendor then reverted a standard service update that appeared to be the source of impact and thought the issue was mitigated on their end. 

However, after monitoring the affected infrastructure, the vendor determined the revert was not a viable mitigation strategy. They announced they would begin gathering "logs from a subset of affected users to refine our understanding of impact and formulate our remediation strategy."

The Outlook app on iOS was not impacted. 

Interruptions to M365 Exchange access via Apple Mail on iOS mobile devices. The Outlook app is not affected.

Update: The vendor and their third-party analysts continue to investigate a complex issue that made Microsoft 365 Exchange email inaccessible in the native iOS mail app on mobile devices on March 3, 2025. The Outlook mobile app is not affected.
 
Previously, Microsoft  announced, "Our collaboration efforts with the third-party are progressing as we continue to collect and analyze logs from affected users. We fully understand the significant impact this incident has had on those affected, and we are treating this matter with the utmost priority and consideration."

Locally, the incident began when some CIT customers reported an issue accessing their M365 Exchange email messages on the iOS native mail application, Apple Mail, on their mobile devices. The vendor reverted a standard service update that appeared to be the source of impact and thought the issue was mitigated on their end. 

However, after monitoring the affected infrastructure, the vendor determined the revert was not a viable mitigation strategy. They announced they would begin gathering "logs from a subset of affected users to refine our understanding of impact and formulate our remediation strategy."

The Outlook app on iOS was not impacted. 

Interruptions to M365 Exchange access via Apple Mail on iOS mobile devices. The Outlook app is not affected.

Update: Microsoft has announced, "Our collaboration efforts with the third-party are progressing as we continue to collect and analyze logs from affected users. We fully understand the significant impact this incident has had on those affected, and we are treating this matter with the utmost priority and consideration."

Earlier this week, some CIT customers reported an issue accessing their M365 Exchange email messages on the iOS native mail application, Apple Mail, on their mobile devices. The vendor reverted a standard service update that appeared to be the source of impact and thought the issue was mitigated on their end. 

However, after monitoring the affected infrastructure, the vendor determined the revert was not a viable mitigation strategy. They announced they would begin gathering "logs from a subset of affected users to refine our understanding of impact and formulate our remediation strategy."

The Outlook app on iOS is not impacted. 

Interruptions to M365 Exchange access via Apple Mail on iOS mobile devices

Update: After monitoring the affected infrastructure, CIT has determined that the vendor's reverting the aforementioned update was not a viable mitigation strategy. We're now in the process of gathering logs from a subset of affected users to refine our understanding of impact and formulate our remediation strategy. 

Previously, some customers reported an issue accessing their M365 Exchange email messages on the iOS native mail application, Apple Mail, on their mobile devices. The vendor reverted a standard service update that appeared to be the source of impact and has validated the issue is mitigated on their end. If you are still experiencing problems seeing your M365 Exchange email in your native iOS mail application, go into your phone mail settings and re-enter your account password.  

The Outlook app on iOS is not impacted. 

Interruptions to M365 Exchange access via Apple Mail on iOS mobile devices

Update: The vendor reverted a standard service update that appeared to be the source of impact and has validated the issue is mitigated on their end. If you are still experiencing problems seeing your M365 Exchange email in your native iOS mail application, go into your phone mail settings and re-enter your account password. 

Previously, some customers reported an issue accessing their M365 Exchange email messages on the iOS native mail application, Apple Mail, on their mobile devices. The Outlook app on iOS is not impacted. 

Interruptions to M365 Exchange access via Apple Mail on iOS mobile devices

Update: CIT is continuing to investigate and isolate the source of impact after some customers reported an issue accessing their M365 Exchange email messages on the iOS native mail application, Apple Mail, on their mobile devices. The Outlook app on iOS is not impacted. 

Interruptions to M365 Exchange access via Apple Mail on iOS mobile devices

Some customers have reported an issue accessing their email messages on the iOS native mail application, Apple Mail, on their mobile devices. CIT is aware and investigating the issue. Outlook on the iOS is not impacted. 

Apple Mail access interruptions on iOS mobile devices