Here is what happened:
After the race to get every thing updated after the security updates lately, I updated my XCP-ng, tightened firewall rules and the NAS settings, updated XOce (debian12) from a5077 of oct 29, after I read the [Security] VSA-2026-062: critical Xen Orchestra vulnerability fixed, please update on nov 10. I ran apt update and node was updated from 24.22.2 to 24.22.3 prior to running the XOce update. Now the backups didn't work.

XOce told me I had no privilege to send backups to the NAS.
If I tried test your remote it was OK. but I could not see any backups to restore.
If I disabled/enabled the remote, I saw them again, but after another faulty backup, they where gone again.
After a lot of testing, I ran the XOce update with 24.22.2 and the backups worked

But I didn't want to run this "old" version of node so I adjusted my Ronivay install script from using node v24 to v26. and now the backups are all happy again.