Hi @DavidB023, See if you can by using the Web data source type in the gateway connection to the SharePoint URL for the Excel file in the Power BI web service portal.
I have been able to have this setup working previously. Also, by looking at your URL you shouldn't be using the .aspx in your data query. The Gateway connection and the query should instead be referencing the file in the SharePoint library i.e. http://site/Library/file.xlsx
There might be another way to setup this connection, however, this was working for my environment.