When configuring an Unstructured Data Backup (often referred to as "NAS backup" or "file share backup") in Veeam, you must add and configure a File Backup Proxy role in your environment. In the Veeam UI and documentation, this role is typically grouped under the broader concept of a Backup Proxy - it's just configured specifically for file-level (unstructured data) processing rather than VM image-level backups.
Backup Proxy (File Backup Proxy role)
Responsible for reading data from file shares or NAS devices and then sending it to the backup repository.
You can deploy it on a Windows or Linux server with access to the file share.