Microsoft Defender for 365 helps protect your organization against potentially malicious messages, like phishing and malware attacks. Your organization can apply a security policy to protect you from potential threats in Teams chats, emails, and other collaboration tools.
Where’s my message?
If you receive one of these notifications, Microsoft believes your message contains potentially malicious content and has placed it in your organization’s secure folder:
To review or retrieve messages, visit your secured folder: end user quarantine. If you do not have access, contact your org's IT admin. To retrieve any messages in your secured folder, contact your org's security admin.