Getting a 403 Error in Copy Activity

Hello everyone,

I am doing a copy activity from sharepoint to blob using this doc: https://docs.microsoft.com/en-us/azure/data-factory/connector-sharepoint-online-list?tabs=data-factory#copy-file-from-sharepoint-online

Since the data in sharepoint is not a list, I am using the second flow using web activity and copy activity.

However I am getting an error in the copy activity.

ErrorCode=HttpFileFailedToRead,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=Failed to read data from http server. Check the error from http server：The remote server returned an error: (403) 

Can anyone guide me why this is happening ? [I followed all the steps in the doc]

Thank you