Some on-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices

Title: Some on-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices

User impact: On-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices.

Current status: We're monitoring the progress of the deployment which has reached 80 percent saturation. A majority of affected users should be remediated at this time and we anticipate the deployment will complete by our next scheduled communications update.

Scope of impact: Some on-premises users attempting to send or receive email messages on iOS and Android mobile devices may be impacted.

Start time: Thursday, August 14, 2025, at 9:00 AM UTC

Estimated time to resolve: We anticipate the deployment of the fix will complete by Monday, August 25, 2025, at 5:30 PM UTC.

Root cause: A recent change to optimize the sync processes between services leveraged in the impacted scenario introduced a code issue that’s leading to the impact.

Next update by: Monday, August 25, 2025, at 5:30 PM UTC

Title: Some on-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices

User impact: On-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices.

Current status: We’ve determined that a recent change to optimize the sync processes between services leveraged in the impacted scenario introduced a code issue that’s leading to the impact. We’re in the process of deploying a fix to address this problem. Users will experience impact remediation as the fix reaches their environments, and we’re monitoring the progress of the deployment to provide an estimation for it reaching all affected users by our next scheduled update.

Scope of impact: Some on-premises users attempting to send or receive email messages on iOS and Android mobile devices may be impacted.

Start time: Thursday, August 14, 2025, at 9:00 AM UTC

Root cause: A recent change to optimize the sync processes between services leveraged in the impacted scenario introduced a code issue that’s leading to the impact.

Next update by: Friday, August 22, 2025, at 5:30 PM UTC

Title: Some on-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices

User impact: On-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices.

Current status: While our review of service logging to identify the underlying cause of this event is ongoing, we're implementing a fix to alleviate the impact. We anticipate the fix will be deployed by our next scheduled communications update, at which time we'll monitor the service to confirm if it’s had any effect in remediating the impact.

Scope of impact: Some on-premises users attempting to send or receive email messages on iOS and Android mobile devices may be impacted.

Next update by: Thursday, August 21, 2025, at 5:30 PM UTC

Title: Some on-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices

User impact: On-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices.

Current status: We're continuing to review service logging to isolate the root cause of this event and establish a fix.

Scope of impact: Some on-premises users attempting to send or receive email messages on iOS and Android mobile devices may be impacted.

Next update by: Wednesday, August 20, 2025, at 5:00 PM UTC

Title: Some on-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices

User impact: On-premises users may be unable to send or receive Exchange Online email messages on iOS and Android mobile devices.

Current status: We're reviewing service logs to determine our next troubleshooting steps.

Scope of impact: Some on-premises users attempting to send or receive email messages on iOS and Android mobile devices may be impacted.

Next update by: Wednesday, August 20, 2025, at 3:00 PM UTC