Script to set shared mailbox permissions fails

I want to use the below link to set permissions for shared mailbox.
https://github.com/michevnew/PowerShell/blob/master/Remove_Folder_Permissions_recursive_BULK.ps1
However I am getting error “no matching security principals found”

My colleague can run this. I am new and have limited permission. Please suggest the permission that I need for running this script.