M365 SharePoint Restore job fails with an error "Failed to Add Administrator to site https://xxxx.sharepoint.com" Or Error code:67113873/1008 for default communication site and apps.

Problem

M365 SharePoint Restore job fails with an error "Failed to Add Administrator to site "https://test.test.test" for default communication site and apps.

Error Message

Restore job fails with Error - Failed to Add Administrator to site "https://test.test.test"

Or

Restore Job completes with Exception - "Error code:67113873/1008. SharePoint site user not found".

Solution

This can be fixed by adding at least one authorized user in the site collection administrator's role.