There is an internal issue stating the above problem that user is unable to connect to Project Online Content Pack, and engineer is working on this issue. I will post back once I get any updates.
Besides, as a temporary workaround for this issue, you can connect to Project Online using Get Data-> OData feed entry in Power BI Desktop following the instructions in this blog , then create your reports and publish them to Power BI Service.
When refreshing the dataset, the error you get should be caused by the same reason as that you get when connecting to Project Online content pack in Power BI Service. This issue is being investigated, your patience is greatly appreciated.
The OData option via the Desktop App appears to be working for me now with the following appended on the end of the URL.
Via the Get Data option in PowerBI.com Correct?
I still have the same issue as you via this method, but this workaround is possible in the Desktop version of PowerBI.
Though not a solution for the problem posted, it is a workaround that allows you to access and work with the data. It is possible to publish to the PowerBI Service online as well, though the data source will not refresh and must be done via the desktop app.
Hope this is useful, I am lookin forward to the App on the service working again also.
As mentioned in the Power BI Support site, regarding to the Project Online content pack issue, engineers are working on preparing the fix. Please take a look the update time.
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