Mind the required permissions for the following user accounts.
User That Performs Veeam Plug-in Installation
The account used for installing and updating Veeam Plug-in must be a member of the local Administrators group. Local administrator permissions are required to install and manage Veeam Plug-in Toolbar in Microsoft SQL Server Management Studio.
User That Performs Backup and Restore
To be able to connect to a Microsoft SQL Server instance, the account used for starting Microsoft SQL Server backup and restore processes must be added to the following roles:
Veeam Backup & Replication User
The account that is used to authenticate against Veeam Backup & Replication must have access permissions on required Veeam backup repository servers. To learn how to configure permissions on repositories, see Granting Access to Repositories.
Veeam Plug-in for Microsoft SQL Server uses Windows authentication methods of the Veeam Backup & Replication server to establish a connection to this server and to the backup target. It is recommended to create one user for each standalone Microsoft SQL Server or failover cluster with Veeam Plug-in.
To work with backups created by Veeam Plug-in, you can use only the same account that was used for creating the backup. If you want to use another account, assign the Veeam Backup Administrator role or Veeam Backup Operator and Veeam Restore Operator roles to the account. To learn how to assign Veeam Backup & Replication roles, see the Users and Roles section of the Veeam Backup & Replication User Guide.