If you are using PowerBI Service and the PowerBI Data Gateway but are having troubles authenticating to your local machine (i.e. you have an excel or csv file that you want refreshed) this may be the post for you.
I use Office365 and have an @yourcompany.onmicrosoft.com account. That’s also the username to login to my computer. But if you pass xxx@yourcompany.onmicrosoft.com as the username it will not work because it doesn’t know what domain to use.
Instead, you must use this format for the username: azuread\xxx@yourcompany.onmicrosoft.com
DIY Accountant 