Sharepoint connection fails credentialing when adding a custom column in Power Query

[Anonymous]

Good morning - 

I have a connection to a Sharepoint list in Power BI. It's been working great, however.. when I try to add a custom column, Power Query and PowerBI both ask me for my Sharepoint credentials. I choose the subsite level, and it tells me that the user is not signed in. I sign in, and it tells me that "We couldn't authenticate with the credentials provided. Please try again". 

Does anyone know what's going on with this, and how to get around it? I was able to add a simple subtraction column in Power Query, but this is an if function grouping this created column:

if DurationValue > 360 then "360 + days"
else if DurationValue >= 90 and DurationValue <= 359 then "90 - 359 days"
else if DurationValue >= 60 and DurationValue <= 89 then "60 - 89 days"
else if DurationValue >= 30 and DurationValue <= 59 then "30 - 59 days"
else "Less than 30 days"

Thank you for any help!

[christinepayton]

Are you using an organizational account type in the credential window? It'll default to anonymous, which won't work. The other thing I've had to do with SharePoint specifically is turn on the "use default browser for authentication" in settings (iirc this was when the auth login window wouldn't pop up properly but it's been a while so mentioning just in case).