Currently the data refresh (refresh now button) does not work in the Power BI service (Premium P1).
Since a few days (maybe since the June Power BI Desktop Update) we receive the following error message:
The XML for Analysis request timed out befor it was completed. Timeout value: sec. An error occurred while attempting to save the dataset.
So far we had no problems here. The refresh in the Power BI desktop works perfectly (with the same gateway and a dataset with about 8 million rows / 350MB). We use an ODBC-Connector with our on-premise Datagateway.
Some planned updates with incementel refreshs work perfectly too.