I think the issue is with the Azure property for the cluster's .arc role. If you go to the roles and administrators for your ClusterName.arc application (not the service principal) and add the account signed into Azure that is attempting to install the Windows Admin Center to the Cloud Application Administrator for the selected scope ClusterName.arc, it allows the installation of Admin Center (unless I just got lucky, but according to the failures from the logs it seems like that was the issue).
Assistance with windows admin center deployment
Nana Poku
305
Reputation points
Having issues with arc-enabled virtual machines extension as it keep telling me your windows admin center extension is in a bad state, please uninstall and re-install.I have uninstalled the windows Admin center extension from the server and then reinstalled it but still getting Failed status for the entension