I am using Veeam Windows Agent Free to back up to a TrueNAS SCALE 25.04 SMB share. Restore using Veeam RE USB stick was fine on CORE - but on SCALE 25.04, I am absolutely not winning.
The symptom is “RPC server is unreachable” and “Remote procedure call failed” from the Veeam recovery environment. That’s with \\IP-of-TrueNAS\backup as the path, and user and password supplied. I tried it with Veeam recovery media created by 6.3.1, 6.3.0, 6.2.0 and 6.1.2. I couldn’t try 6.1.0 because that no longer managed to log onto WiFi 
On the TrueNAS side I verified that my share is set to “default share parameters”, not multi-protocol or anything. I blew away the ACL and recreated it, didn’t change anything. I looked in /var/log/samba4/log.smbd but saw nothing logged for these attempts by Veeam.
I’m at a loss. Without restore, Veeam is a little useless. Backup works great - the backup share is reachable from Windows 11 24H2, but somehow the restore environment can’t access the share. Though that restore environment is also a Windows, just Windows RE.
If you have this working against SCALE 25.04: Please share how your SMB share and SMB service is set up, version of Veeam you’re using to recover, and any special shenanigans you had to undergo to make it work, if any.