Microsoft 365 Alert – Service Degradation – Exchange Online – Users may be unable to share their Outlook calendars externally across any Exchange Online connection method – NEW
10/01/2025 07:40:00 AM
NHSmail Reference: INC47951149
Microsoft Reference: EX975862
Issue Status: OPEN
Issue Description: Users may be unable to share their Outlook calendars externally across any Exchange Online connection method.
Current Update: 10/01/2025 07:40:00 AM – Microsoft are rolling back the impacting migration as a temporary solution while they work on developing a long-term fix. They anticipate this roll back process will be completed by Tuesday, January 14, 2024.
Scope of impact: Impact may occur for any user attempting to externally share their Outlook calendars across any Exchange Online connection method.
Root cause: A recent migration for a service that supports external calendar sharing is causing a section of Outlook calendar infrastructure to operate below acceptable performance thresholds.
Next Update by: Saturday, January 11, 2025, at 6:30 AM UTC