Microsoft is currently investigating Issue ID EX1464935, a service incident affecting Exchange Online that may cause users to experience email delivery failures, delays, and authentication-related issues when accessing Microsoft 365 services. According to reports, organizations have seen problems with sending and receiving email, while some users have encountered intermittent sign-in and access issues tied to Exchange Online services.
How This Affects Users
Users may experience:
- Delayed or undelivered emails.
- Intermittent authentication and sign-in failures.
- Difficulty accessing Outlook on the web or Exchange-connected applications.
- Disruptions to business communications that rely on Microsoft 365 email services.
What Organizations Should Do
While this issue is being addressed by Microsoft, businesses should:
- Monitor the Microsoft 365 Admin Center for updates related to EX1464935. – https://admin.cloud.microsoft/?#/servicehealth/:/alerts/EX1464935
- Advise users that email delivery may be delayed and to avoid repeatedly resending messages.
- Use alternate communication channels such as Microsoft Teams when necessary.
Security Perspective
At this time, Microsoft has identified the issue as a service availability problem rather than a cybersecurity incident. However, outages often create opportunities for phishing attempts that impersonate Microsoft support or service notifications. Organizations should remain vigilant and rely only on official Microsoft communications for status updates.