How can I export mailing list contacts via API call?

Hello,
The above power query script looks just like what I need, but I can't get it to work on my mailing list. Does this still work for other people?
I made the updates to datacenter, mailing list ID, and the API-token (and also to the line "each [i]null" which appears to be a typo).
All I get for output is 150 null records, and nothing at all if I filter out nulls. Does that mean that I'm just not connecting? I'm not getting any error messages.
Any kind of help would be greatly appreciated!
The code I used (except the API token and mailing list ID) is below.

let
 iterations = 150,
 url = "https://iad1.qualtrics.com/API/v3/mailinglists/ML_???/contacts", 

 FnGetOnePage = (url) =>
  let
  Source = Json.Document(Web.Contents(url, [Headers=[#"X-API-TOKEN"="???"]])),
  data = try Source[result][elements] otherwise null,
  next = try Source[result][nextPage] otherwise null,
  res = [Data=data, Next=next]
  in
  res,
 
 GeneratedList =
 List.Generate(
  ()=>[i=0, res = FnGetOnePage(url)],
  each [i]  each [i=[i]+1, res = FnGetOnePage([res][Next])],
  each [res][Data])
in
  GeneratedList

Hi All,

Came across this and this is really interesting. I ready though that there was a difference between ML_ vs CG_ lists (RC / XM or Shared / Non Shared)? Did anyone get this working?
Thanks
Rod Pestell