C:\Program Files\Veeam\Backup and Replication\Backup>Veeam.Backup.Validator.exe /backup:"Backup Lucius"
Veeam Backup Validator Version 12.0.0.0
Copyright (C) 2023 Veeam Software Group GmbH. All rights reserved.
The SQL Server machine hosting the configuration database is currently unavailable. Possible reasons are a network connectivity issue, server reboot, heavy load or hot backup.
Please try again later.
Error:
SSPI authentication failed for user "postgres"
It seems that, when Veeam B&R is using postgres as it's database, the validator is trying to connect to MSSQL instead ?
It works fine in my lab with PostgreSQL. Just tested with Agent backups on my VBR server.
If you have updated your backup chains to the new v12 format, please use this KB to validate the backup files: https://www.veeam.com/kb4485
A support case is required if you still face issues with the validation.