Hi Guys,
I hade the same problem. A tried many things. Finally this article gave mi a hint: https://learn.microsoft.com/en-gb/answers/questions/1632654/azure-stack-hci-23h2-deployment-fails-due-to-a-spa
I have changed the names of the network interfaces in a way that they do not contains spaces. (for Example from: "PCIe Slot 3 Port 1" to "MGMT01".) I did it with all the adapters. After that I had to change the interfaces in the wizard on the Azure portal too.
(I have opened a ticket too and the engineer confirmed that it is recommended to not have a space in the names of the network adapters.)
Then the validation was successful. I hope it will help!
Bests,
Ákos