Just a quick post today to share a fix for an error that I have come across multiple times on Power BI Desktop and Excel Power Query when refreshing reports.

 “Access to the Resource is Forbidden”  

When receiving this message on Power BI Desktop for a SharePoint online data source or other data sources, do the following:

1. Update the Power BI desktop to the latest version
2. Ensure that the account you are using to authenticate on Power BI Desktop has full access to the data source and the file location/Permission has not change in SharePoint.
3. On Power BI Desktop Clear or Edit the Data source permissions: From Home >> Transform Data >> Data source Settings >> Clear permissions or
   Home >> Transform Data >> Data source Settings >>Edit permissions >> Edit >> Sign in as different User (With the account you used to access the SharePoint Site) Save and close.
4. On your Computer go to the following path: C:\Users\ username\Microsoft\Power BI Desktop Store App and rename the Zip folder User.zip to User1.zip. This will also clear all previous user logins caches and will create a new user folder.

Your data connection should now be successful.

If you are using Excel Power Query, go to the following Path C:\Users\yourusername\ AppData\Local\Microsoft\Office\16.0\PowerQuery and rename the Zip folder User.zip to User1.zip and repeat step 4