I've created a new Data Source using "Manage Gateways." This setup shows the "Connection Successful" message. I've created a new report in Power BI Desktop, carefully created the Get Data connection in the same way, and published to the web. I mapped the new dataset's Scheduled Refresh to use the On-prem Gateway via the radio button and selected the appropriate time-based refresh schedule.
When this dataset attempts to run via "Refresh Now" I receive a "Invalid connection credentials" message instantly. My account owns the Workspace (as Admin), owns the Gateway (as Admin), and belongs to the Data Source (via Users).
When this datasets attempts to run via its Schedule it runs for 10+ minutes before returning "Invalid connection credentials."
If I run the query locally, in SSMS, using the same credentials as the Data Source the SQL returns correct data in just a few seconds.
We see no corresponding error message within the Sql Server logs. This implies the query has never escaped from the cloud.
Any ideas?