PowerBI Service: Data Set Refresh Failure

i Xiaoxin, 

The data source used is a "Sharepoint folder". 

The sharepoint site is the site that is created for the PowerBI Service Workspace I published the report to. 

This is not an on-premises date source so I've been connecting directly and not through an on-premises gateway. 

I'm not doing scheduled refreshes at this time. Only manual refreshes. I'm ensuring I've authenticated appropriate prior to hitting refresh by signing in through the OAuth setting. 

I've reviewed the troubleshooting link you provided and the only info I could was as follows:

"Microsoft is investigating a solution that allows the data loading process to refresh the token and continue. However, if your Dynamics CRM Online or SharePoint Online instance (or other AAD OAuth data source) is so large that it could run into the two-hour data-load threshold, you may experience a data load timeout from the Power BI service as well.

Also note that, for refresh to work properly, when connecting to a SharePoint Online data source using AAD OAuth, you must use the same account that you use to sign in to the Power BI service."

I do not believe the 2hr time-limit is  what's causing this issue as the time-out occurs much earlier than 2 hrs. A full refresh on my local laptop with 8gig of ram takes less than 2hrs as well, I would assume that PowerBI Service would be able to complete this refresh even quicker than that. This refresh failed within 5min. 

The refresh fails 95% of the time but in the rare 5%, it succeeds. If there was a setting issue the failure would be consistent.

Is there a bandwidth limit on refreshes? My dataset is only 4gb in size.