Microsoft Defender XDR Unified RBAC | Tenant Allow/Block List, entry addition error

Hello a-rapsomanikis,

We are experiencing some issues with Invited guests and their access to some MDO experiences , that were previously controlled by EXO roles (this is including TABL).

As a temporary workaround, you may need to disable Defender XDR RBAC for Email & Collaboration / Exchange Online section. 

You may also need to re-assign the Entra ID roles in the Microsoft Admin Center
go to https://admin.microsoft.com/#/rbac/directory > select "Exchange" roles tab > search for a "Security Administrator" role group > in the Security Administrator role group flyout, select "Permissions" tab > select "Security Admin" and click save.