I don't understand why and what I did wrong. The post is clearly almost a copy of a part of a previous answer on the same thread. The only added information is very minor: the database name and schema
ReportServer.dbo.. I don't remember when I flagged that answer, but probably was in the low quality queue (not sure). Anyway it should not be an answer as per SO guidelines, it is really a so small a contribution it should be in a comment.
What did I miss?