Users' outbound Exchange Online email messages may be incorrectly flagged as spam

Microsoft Service Incident: Updates from Microsoft - User Impact - Users' outbound Exchange Online email messages may have been incorrectly flagged as spam. More info - Impact was specific to senders protected by the default outbound spam policies. Admins may have received copies of the flagged email messages. Scope of Impact - Any user attempting to send outbound Exchange Online email messages was impacted. Root Cause - A recent change to our model for filtering outbound email messages as spam caused impact. Next Steps - A recent change to our model for filtering outbound email messages as spam caused impact. Dec 4, 2024, 5:22 PM CST We've disabled our recent changes to the model for filtering outbound email messages as spam and confirmed through our mail filtering telemetry that the impact is remediated.