Challenge
SharePoint Online or OneDrive for Business backup jobs fail with the following message:
2/5/2020 5:32:43 PM :: Processing site https://site.sharepoint.com/sites/111/subsite finished with warning: Failed to backup item version: /<path>/1024/Shared Documents/<file>, version: 2.0, The remote server returned an error: (403) Forbidden. :: 0:00:21
Cause
Due to limitations of history of file versions, files cannot be downloaded.
Solution
To confirm the limitations of history of file versions, do the following:
1. Open the affected OneDrive or Site in the Web-browser.
2. Find the file that cannot be downloaded and open Version history.
3. Left-click the date.
If the 403 error appears, that means that the file is inaccessible in Office 365. Make sure to contact Microsoft Technical Support.
If you are getting any other error, make sure to contact Veeam Technical Support.