Configure SSRS Report Data Source Link programmatically via PowerShell or Console Application

Question

I require to set the data source link of SSRS reports.

The SSRS Reports and the Data Source reside in a document library. I want to set the shared data source for all the SSRS reports of the document library.

I tried to achieve it using PowerShell and by consuming the SSRS Report Service in a console application. But in both the approaches, I faced below issues:

1. Getting the Data Source associated with an SSRS report using GetItemDataSources:

Exception calling "GetItemDataSources" with "1" argument(s): "Report Server has encountered a SharePoint error. ---> Microsoft.ReportingServices.Diagnostics.Utilities.SharePointException: Report Server has encountered a SharePoint error. ---> Microsoft.SharePoint.SPException: The user does not exist or is not unique.

2. While reading the contents of the root folder of the SSRS report document library which contains all SSRS reports using ListChildren:

Exception calling "ListChildren" with "2" argument(s): "The permissions granted to user 'NT AUTHORITY\ANONYMOUS LOGON' are insufficient for performing this operation. ---> Microsoft.ReportingServices.Diagnostics.Utilities.AccessDeniedException: The permissions granted to user 'NT AUTHORITY\ANONYMOUS LOGON' are insufficient for performing this operation."

Any help will be grateful!!!