KB #1017: The restore could not be completed because a permission is missing in Application registration in Microsoft Azure
Cause
Unable to connect to the resource. The specified Azure AD application is missing required delegated permissions (Microsoft API: Microsoft Graph, permissions: Sites.Read.All). As the error describes a permission is missing within Microsoft in order to restore.
Solution
Log in to Microsoft Azure portal using Administrator with global admin rights. https://portal.azure.com
In the top search bar search for the ID supplied in the error message.
Select the Application in the search result.