Unable to get reports with API

Hello I have encountered the same problem now, but I always fail to call the creation interface. I am using C# and the interface always returns: “The request could not be understood by the server due to malformed syntax”. I use the post method, The text passed is

{
“report”: {
“name”: “A new app report”,
“shopify_ql”: “SHOW total_sales BY order_id FROM sales SINCE -1m UNTIL today ORDER BY total_sales”
}
}
Can you tell me what went wrong?