Enable end user notifications for end users who have quarantined emails within Microsoft. End users will receive a summary of held emails for User Quarantined emails where they have the option to review and release emails.
Navigate to https://security.microsoft.com/antispam
Select “Edit Actions” under “Actions”
Ensure the notifications are set to the highlighted below:
Navigate to https://security.microsoft.com/quarantinePolicies
Ensure “Quarantine Notification” is enable