Permission & Access Issues

How to Assign Admin Rights Across Microsoft Entra ID Tenants

Elise Williams Oct 9, 2026 869 views

Question details

An IT administrator needs to grant a user from one Microsoft Entra ID tenant administrative rights to manage another tenant's Microsoft 365 resources without using a Cloud Solution Provider (CSP) setup.

How to Assign Administrative Rights Across Microsoft Entra ID Tenants

Product: Microsoft Entra ID
Device & OS: not provided
Scenario: Setting up cross-tenant administration using external user invitations (B2B) for managing Microsoft 365 resources like SharePoint.
Observed behavior: The user is successfully invited as an external user, but encounters an error stating external sharing is disabled when attempting to use SharePoint administrator access.

Before you start

Ensure you are signed into the target Microsoft Entra ID tenant with a Global Administrator account to configure cross-tenant access settings and assign administrative roles.

Solution 1Recommended

Verify Microsoft Entra B2B Roles and Cross-Tenant Access

Use this solution to confirm the external user has the correct directory roles and that your tenant allows inbound administrative access from their home tenant.

Inviting a user from another tenant as an external user automatically utilizes Microsoft Entra B2B collaboration. To allow this user to manage resources, you must explicitly assign them the appropriate administrator roles in the directory and ensure cross-tenant access policies do not block their permissions.

Navigate to Microsoft Entra admin center

Sign in to the Microsoft Entra admin center for the target tenant, expand the 'Identity' menu, and select 'Users' > 'All users'.

Assign Administrator Roles

Search for the invited external guest user and click on their profile. Navigate to 'Assigned roles', click 'Add assignments', and assign the necessary roles (such as Global Administrator, SharePoint Administrator, or Teams Administrator).

Check Cross-tenant access settings

Go to 'External Identities' > 'Cross-tenant access settings'. Under the 'Organizational settings' tab, verify that the inbound access settings for the external user's home tenant are configured to allow B2B collaboration and trust their multifactor authentication (MFA) claims if required.

Verify Microsoft Entra B2B Roles and Cross-Tenant Access

Role Propagation Delay: It can take up to a few hours for newly assigned directory roles to fully propagate across all Microsoft 365 services for guest users.

Solution 2

Configure SharePoint External Sharing Policies

Apply this fix if the external user is an admin but receives errors stating that external sharing is disabled when trying to manage SharePoint resources.

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Frequently Asked Questions

Can an external B2B user be a Global Administrator in Microsoft Entra ID?

Yes, external guest users invited via Microsoft Entra B2B can be assigned administrative roles, including Global Administrator, to manage resources in the host tenant.

Why does SharePoint say external sharing is disabled for my administrative guest?

Even if a guest has SharePoint Admin rights, organization-level or site-level sharing policies take precedence. You must configure SharePoint sharing settings in the admin center to allow 'New and existing guests' to resolve this conflict.

Do I need a Cloud Solution Provider (CSP) agreement to manage multiple Microsoft 365 tenants?

No. While a CSP arrangement is common for managed service providers managing many clients, you can use Microsoft Entra B2B collaboration to grant individual administrative access across tenants directly.

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