Data source credentials greyed out.

Try using SharePoint or OneDrive for Business links, not Teams shortcuts. For SharePoint files, it is more reliable to use Power BI built-in connector SharePoint Folder and Web connector for OneDrive with the correct file URL (direct path, not a sharing link).

If you are still seeing Data Source Credentials greyed out, you may check this post here

Solved: Data Source Credentials is greyed out & Sharepoin... - Microsoft Fabric Community 

Hi Anonymous 

You can get the url from detail info of excel file, as below:

Then, use below PowerQuery expression to read the data:

let
    ExcelFileUrl = "pls input excel file url here",
    SheetName = "pls input sheetname here",

    ExcelWorkbook = Excel.Workbook(Web.Contents(ExcelFileUrl),true,null),
    Result = ExcelWorkbook{[Item=SheetName,Kind="Sheet"]}[Data]
in
    Result

Did I answer your question? If yes, pls mark my post as a solution and appreciate your Kudos !

Thank you~