Based on your support case error messages, it looks like our InGuest component can not interact with the VM to do what Veeam needs to do.
Our support sent you some ideas that you can test with one of the VM. If it helps you can do the same with the other VMs.
Maybe another option is that another backup software is actually taking backups. Do you have any Agents or SQL Managment Studio Backups running at same time?
In general, when I looked up the error message from the logs, I found some older fixes from Microsoft ... for example:https://support.microsoft.com/en-in/hel ... in-windows
Maybe just check one more time if the windows servers are up to date.