Hi @VANESSA JIANG ,
According to my research, you must be a global administrator or a security administrator in Microsoft Entra ID to access Microsoft 365 Defender. For the list of roles required to use Microsoft 365 Defender and information on how access to data is regulated, read about managing access to Microsoft 365 Defender.
Go directly to the Restricted entities page, use https://security.microsoft.com/restrictedentities
More information, see: Remove blocked users from the Restricted entities page
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