Hi @yagmur ,

Did you assigned required permission to service principal on storage account?
And make sure you're configuring connection to storage account in proper way. You should have something similiar to the code below:

configs = {
            "fs.azure.account.auth.type"              : "OAuth",
            "fs.azure.account.oauth.provider.type"    : "org.apache.hadoop.fs.azurebfs.oauth2.ClientCredsTokenProvider",
            "fs.azure.account.oauth2.client.id"       :"your_client_id",
            "fs.azure.account.oauth2.client.secret"   : "your_secret",
            "fs.azure.account.oauth2.client.endpoint" : f"https://login.microsoftonline.com/your_tenant_id/oauth2/token"
        };

dbutils.fs.mount(
                    source = f"abfss://your_container@your_storage_account.dfs.core.windows.net/",
                    mount_point = f"/mnt/your_mount_point_name",
                    extra_configs = configs
                    );
             

 Anyway, nowadays you should use Unity Catalog and configure storage using Storage Credential