Please confirm you are running Veeam Backup for Microsoft Office 365 version 220.127.116.117 prior to installing this cumulative patch KB2765. You can check this under Help > About in Veeam Backup for Microsoft Office 365 console. After upgrading, your build version will change to 18.104.22.1684.
As a result of on-going R&D effort and in response to customer feedback, cumulative patch KB2765 brings optimizations to SharePoint Online and OneDrive for Business interactions and processing making backup jobs less affected by throttling, and includes a set of bug fixes, the most significant of which are listed below:
• Discovery Search Mailbox may consume a license when included into a backup job.
• Under certain conditions resource mailboxes may consume a license.
• SharePoint Online and OneDrive for business backup jobs may fail with the “Specified argument was out of the range of valid values” error. More details in KB 2713.
• SharePoint Online personal sites may have duplicate names displayed in a Backup Job wizard.
• Backup of SharePoint Online and OneDrive for Business items with an incorrect last modified date may fail with the “Item not found in the database” error.
• SharePoint Online and OneDrive for business backup jobs may fail with the “Failed to backup item: , The remote server returned an error: (404) Not Found” warning.
• Group mailbox backup may fail with the “Failed to find group owner account” warning.
• Private Office 365 group backup may fail, if a group owner has more than one record in Office 365.
• In hybrid organizations, shared mailbox backup job may fail with the “Unspecified error”.
• Collecting Veeam Backup for Microsoft Office 365 logs with remote console may fail with the “Object reference not set to an instance of an object” error.