Unable to Activate Windows Server 2025 VM on Truenas Scale

I’m unable to activate a Server 2025 VM running on Truenas Scale 25.10.2 - Goldeye.

I’m using VirtIO for both disk and network. I can domain join the VM OK, but it says it can’t reach our KMS server. Testing with test-netconnection -Computername our.kms.server -Port 1688 shows I can reach the port on the KMS server, and Wireshark also shows a normal TCP session between the VM and the KMS server.

VMs running on VMWare are activating OK.

I’ve tried rebuilding the VM three times, but I get the same result each time.

The VirtIO NIC driver is 100.101.104.28500. That was the latest I could find last Friday.

The host is a Dell Poweredge R250 with the latest firmware and drivers as of 1 week ago.