Error Code 4: Invalid value passed for JSONString

Error Code 4: Invalid value passed for JSONString

Okay, I want to start by saying I know I'm a terrible scripter, so sorry if this is a dumb mistake. I just can't figure it out, even with LLM help.

Here's my code:
  1. // --- Input Variables ---
  2. customer_id = salesorder.get("customer_id");
  3. so_id = salesorder.get("salesorder_id");
  4. org_id = organization.get("organization_id");
  5. so_lines = salesorder.get("line_items");

  7. // --- Build Retainer Body ---
  8. retainer_body = Map();
  9. retainer_body.put("customer_id", customer_id);

  11. // --- Handle Custom Fields (Correctly as a List) ---
  12. cf_list = list();
  13. so_cf = Map();
  14. so_cf.put("index", 1);
  15. so_cf.put("show_on_pdf", false);
  16. so_cf.put("value", so_id);
  17. so_cf.put("label", "Sales Order");
  18. cf_list.add(so_cf);
  19. retainer_body.put("custom_fields", cf_list);

  21. // --- Handle Line Items (Correctly as a List) ---
  22. line_list = list();
  23. for each line in so_lines
  24. {
  25. line_map = Map();
  26. line_map.put("description", line.get("group_name") + " " + line.get("description"));
  27. line_map.put("rate", line.get("item_total"));
  28. line_list.add(line_map);
  29. }
  30. retainer_body.put("line_items", line_list);
  31. info "Final payload being sent: " + retainer_body;

  33. // --- API Call with Correct Syntax ---
  34. retainer_invoice = invokeurl
  35. [
  36. url: "https://www.zohoapis.com/inventory/v1/retainerinvoices?organization_id="+org_id
  37. type: POST
  38. parameters: retainer_body
  39. connection: "zom"
  40. ];

  42. info retainer_invoice;

  44. // --- Return Success ---
  45. resultMap = Map();
  46. resultMap.put("message", "Retainer Invoice created from Sales Order: " + so_id);
  47. resultMap.put("code", 0);

Shockingly, I managed to do this almost entirely by myself. The only error that the LLM accurately caught was that my code for the custom field was not properly formatted as a list.

The error / log I'm getting is below:

I assume there's something wrong with the formatting of the retainer_invoice map being sent in the API call?

Here's the entirety of that map, as copied from the log:
  1. {"customer_id":"2245303000022841066","custom_fields":[{"index":1,"show_on_pdf":false,"value":"2245303000144413026","label":"Sales Order"}],"line_items":[{"description":"Pet Door - WM-L (blk) Pet Door - WM-L (blk)","rate":379},{"description":"Pet Door - DM-L (brwn) Pet Door - DM-L (brwn)","rate":798}]}
Any guidance would be greatly appreciated.