Hi @Glenn Maxwell ,
It's the different permission scopes. Actually, the url starts with http://sharepoint/content/, you should not replace sharepoint with your tenant name.
SharePoint supports four different permission scopes. You could refer to this article for more: https://learn.microsoft.com/en-us/sharepoint/dev/sp-add-ins/add-in-permissions-in-sharepoint
If you do not recall what permissions you have given, you could regranted the permission through the url https://contoso.sharepoint.com/sites/TeamSite01/_layouts/15/appinv.aspx
. It will override the permission you have given before.
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