You have an Azure Active Directory (Azure AD) tenant named contoso.onmicrosoft.com. The User administrator role is assigned to a user named Admin1. An external partner has a Microsoft account that uses the user1@outlook.com sign in. Admin1 attempts to invite the external partner to sign in to the Azure AD tenant and receives the following error message: `Unable to invite user user1@outlook.com `" Generic authorization exception.` You need to ensure that Admin1 can invite the external partner to sign in to the Azure AD tenant. What should you do? 

Answer options:

A. From the Users blade, modify the External collaboration settings.
B. From the Custom domain names blade, add a custom domain.
C. From the Organizational relationships blade, add an identity provider.
D. From the Roles and administrators blade, assign the Security administrator role to Admin1.

A

Reference: https://techcommunity.microsoft.com/t5/Azure-Active-Directory/Generic-authorization-exception-inviting-Azure-AD-gests/td-p/274742