No databases shown for Data Explorer

I’m trying to connect to an Azure Data Explorer free instance.
I have setup the service principal and added viewer role to the Data Explorer database, I even added admin user rights to the database.
When I connect Grafana to this datasource the connection is fine but it cannot load any databases/tables, the list is empty.

I can succesfully ingest data with the same service principal.

This happens both with Grafana Cloud and local install of OSS edition.
However I can succesfully connect to a paid Data Explorer instance, so this seems to be a problem only for my DataExplorer free account.

Any clues as to what might be causing this? Or how to debug this further