Dataflow Failure

Hii PowerZBI 

A 429 error in Power BI Dataflows indicates throttling (too many requests or resource contention). This can happen during scheduled refreshes when multiple dataflows or datasets refresh at the same time, or when the source system enforces rate limits. Since the refresh succeeds when run manually, it’s likely a temporary capacity or source-side limit. To reduce this, stagger refresh schedules, avoid overlapping refreshes, reduce dataflow complexity/API calls, and check if the source has request limits. If the issue persists, it’s recommended to monitor capacity usage or raise a Microsoft support ticket.

Hi! PowerZBI 

This could be due to the throttling issue. Try changing it to different time or maybe different sharepoint site. You can also refer to old solutions if that helps.

https://community.powerbi.com/t5/Desktop/DataSource-Error-Web-Contents-failed-to-get-data-from-500/m-p/392703

https://community.powerbi.com/t5/Desktop/DataSource-Error-Web-Contents-failed-to-get-contents-from-app/m-p/2417545

https://community.powerbi.com/t5/Power-Query/DataSource-Error-Web-Contents-failed-to-get-contents-from-URL/m-p/2181574

If you have a Pro license you can open a Pro ticket at https://admin.powerplatform.microsoft.com/newsupportticket/powerbi