Please confirm you are running Veeam Backup for Microsoft Office 365 builds 4.0.1.531 or 4.0.1.545 prior to installing this cumulative patch KB4083. You can check this under Help and Support > About in Veeam Backup for Microsoft Office 365 console. After upgrading, your build version will change to 4.0.1.612.
As a result of on-going R&D effort and in response to customer feedback, cumulative patch KB4083 provides a set of enhancements and bug fixes, the most significant of which are listed below.
Faster listing of backed up OneDrive for Business accounts with the (GET) v4/RestoreSessions/{restoreSessionId}/Organization/OneDrives resource.
To install the cumulative patch KB4083:
If you are using Veeam Backup for Microsoft Office 365 RESTful API Service, restart it manually after you install the abovementioned updates.
If there are any remote proxies in your environment, please update those as described here.