Report keeps loading and spinning without power bi error event being logged

Hi all, 

we provided embedded report to customers and collected telemetry. Lots of customers seems to have the load event and not render event, and there is no power bi error event being logged. Anyone has idea what this is about?

My suspicion is that it takes forever to load the dataset, but I am not so sure and is there anyway that we can log the issue if the dataset keeps loading?

Thanks!