Sometimes I get some strange errors at creating a managed Kubernetes Cluster in Azure (AKS). There errors are in most cases ServicePrincipleNotFound:

The problem was the node size! You can select the node size in the portal during the creation process:

And the portal lists all maschine sizes that are possible and all not possible sizes are deactivated in the list. But the list is not correct, the list does not filter for the service you selected. Instead, it seems to filter only on the region you selected.

Since Azure CLI 2.0.32 you get a correct error message about the wrong node size.

The solution is to use the Azure CLI and get the possible values via TAB²: