Information about the M365 issue on Thursday, September 11, 2025

On Thursday, September 11, 2025, students experienced a major disruption in M365 services. As a result, logging into many services failed, and for example, email and Moodle were not working.

The services were restored around 15:40 the same day. If you were unable to participate in teaching due to the disruption, please contact your teacher (the person responsible for the course) and ask about the possibility of a substitute assignment, unless the teacher has already provided information about it.

Please note that if someone tried to send you email during the disruption, the messages may not have been delivered. If the message was sent via Outlook, the sender received an error notification. However, if the message was sent through another system (e.g., Moodle), the sender may not have received any notification, even if the message wasn’t delivered. Teachers have been informed about this issue.

The disruption was caused by a Microsoft synchronization tool used in the update. The tool was unable to handle multiple group memberships, which are used in our system. The issue was resolved by updating the tool to a newer version. Student M365 account security has not been compromised, and all data is safe.

Last updated: 12.9.2025