Zoho Books API

Zoho Books API

Hello,

I'm trying to use the geturl function in Zoho Creator for Zoho Books:

X = input.Invoice_ID.toString();
headerMap = Map:String({"Authorization":"Zoho-authtoken <CODE>"});
x = getUrl(" https://books.zoho.com/api/v3/invoices/" + X + "?organization_id=452140211",headerMap);

As a response I get: 
{"code":2,"message":"Invalid value passed for organization_id"}
What am I doing wrong?