Error Message: Unable to access Team destination1 SharePoint site. ---> Error connecting to target SharePoint site: SharePointSiteURL, Error: Cannot Retrieve List: Access denied. You do not have permission to perform this action or access this resource.
Cause: This happens when the destination migration admin account is not a Global Admin in the destination tenant.
Resolution: To resolve this either:
Update the account being used to a Global Admin role
Create a new Global Admin account in the destination and use that new Global Admin account in the destination endpoint of the Teams migration project.