Microsoft 365 Alert – Service Degradation – Exchange Online – Users may have seen an English user interface for Outlook on the web on mobile when configured for non-English language – RESOLVED

Announcements Arpan Das

06/01/2025 08:53:00 AM

NHSmail Reference: INC46717112

Microsoft Reference: EX1213757

Issue Status: RESOLVED

Issue Description: Users may see an English user interface for Outlook on the web on mobile when configured for a non-English language

More info: Impacted users would see an English user interface for Outlook on the web when accessing the service through mobile devices on both Android and iOS, even when the user interface configuration was set to alternate languages.

Final Update: 06/01/2026 15:45:00 AM – Microsoft has identified that a recent service update contained misconfigured localization data, resulting in impact. They have rolled back the problematic changes throughout the affected environment and confirmed through internal testing that impact is remediated.

Scope of impact: Users accessing Outlook on the web through mobile devices with their user interface language set to non-English languages may have been impacted.

Root cause: A recent service update contained misconfigured localization data, resulting in impact.

Next Steps: Microsoft are reviewing their update testing and validation methods to better identify issues such as this prior to deployment so we can prevent similar impact in the future.