Power BI Data Service v Desktop Refresh

It's not an SQL query. The key steps are basically:

- StepA uses = SharePoint.Files() to pull a full list of documents, then subsequent steps select the latest file in a folder...

- StepG opens the content from the CSV file, and ultimately pulls out a list of stock tickers

- StepN uses Csv.Document(Table.SelectRows(SharePoint.Files())) - no longer using Web.Contents() to open a static CSV file which converts (via a merge in StepR) the tickers from one format to another

- then source = Json.Document(Web.Contents()) to ultimately invoke an API with the headers that feature the tickers collected and converted in the steps above...

So I think the dependencies following on from one another causing the issue in the service? It all works fine in Desktop, just not service. I have all privacy levels set to Organisational.