Hello, @IniobongNkanga-8038,
Welcome to the Microsoft Q&A platform!
Based on your description, I understand that you are experiencing some challenges with user synchronization in a multitenant setup.
Here are some steps that might help you troubleshoot and resolve this issue:
1. External Sharing Settings: Ensure that the external sharing settings for your organization allow sharing with users from the participating tenant. This can be configured in the SharePoint admin center and the Teams admin center. You can click on Your organization's policies do not allow you to share with these users error when sharing an item or site in SharePoint Online or OneDrive for Business - SharePoint | Microsoft Learn for reference.
2. Check Cross-Tenant Synchronization Settings: Ensure that cross-tenant synchronization is properly configured in Microsoft Entra ID (formerly Azure AD). This involves setting up synchronization rules and ensuring that the necessary permissions are granted.
3. Verify User Sharing Settings: In the Microsoft 365 admin center, go to Settings>Org settings>Organization profile>Multitenant collaboration(Settings - Microsoft 365 admin center). Make sure that the users you want to share are selected and that the synchronization configuration is correctly set up.
4. Provisioning Logs: Check the provisioning logs in Microsoft Entra ID to identify any errors or issues with the synchronization process. This can provide insights into why new users are not being synchronized.
5. User Properties Synchronization: Confirm that the necessary user properties are being synchronized between tenants. This includes properties like email, display name, and job title, which are essential for collaboration in Teams and other Microsoft 365 services.
For more information, please refer to Synchronize users in multitenant organizations in Microsoft 365 - Microsoft 365 Enterprise | Microsoft Learn.
If you've checked these settings and are still experiencing issues, it might be helpful to revisit the configuration steps.
If the answer is helpful please click on ACCEPT ANSWER as it could help other members of the Microsoft Q&A community who have similar questions and are looking for solutions.
Thank you for your support and understanding.
Best Wishes,
Alex Zhang