Report refresh issue

when you merge data from On-Prem and SharePoint online the merge operation happen on your Gateway only thus you have to enable "Allow user's cloud data sources to refresh through this gateway cluster" option in Gateway setting. (Merge or append on-premises and cloud data sources - Power BI | Microsoft Docs)

If you want to SharePoint process not to run on gateway follow below steps

1. Create dataflow for On premise data using gateway connection

2. In your dataset replace onpremise source with Dataflow

Now your merge opration will be perfoemed online and you will not be requing to enable "Allow user's cloud data sources to refresh through this gateway cluster" option anymore.

Solved: Re: does SharePoint Online use gateway even when n... - Microsoft Power BI Community

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