UrlFetchApp.fetch() Exception: DNS error in Google Forms Trigger - google-apps-script

Question

I've attached the following code to a Submit Button in Google Forms:
function generateQueryString(data) {
const params = [];
for (var d in data)
params.push(encodeURIComponent(d) + '=' + encodeURIComponent(data[d]));
return params.join('&');
}
function ctrlqFormSubmit(event) {
// The event is a FormResponse object:
// https://developers.google.com/apps-script/reference/forms/form-response
var formResponse = event.response;
// Gets all ItemResponses contained in the form response
// https://developers.google.com/apps-script/reference/forms/form-response#getItemResponses()
var itemResponses = formResponse.getItemResponses();
// Gets the actual response strings from the array of ItemResponses
var responses = itemResponses.map(function getResponse(e) { return e.getResponse(); });
// Post the payload as JSON to our Cloud Function
var response = UrlFetchApp.fetch('http://<**MY DOMAIN HERE**:3001>/formdir?' + generateQueryString(responses));
Logger.log(response.getContentText());
}
Unfortunately, the Trigger fails with the message:
Exception: DNS error: http://**MY DOMAIN HERE**:3001/formdir?0=Name&1=&2=Biz&3=Research&4=&5=&6=&7=&8=Other&9=&10=&11=&12=&13=&14=
at ctrlqFormSubmit(SubmitFcn:18:30)
But if I copy this exact string in my browser, I get the expected result. Also, when I use NSLOOKUP with this domain on the command line, the IP's return as expected. The domain even resolves when I go to https://dns.google/...
The text of error itself seems to indicate the function is working, and it's a GET request, which is why I'm using Query Parameters, but the DNS name is not resolving in the script. I even used one of the IPs and got the same error.

Answer 1

SOLVED: Even though the domain used above was public-facing, the AWS Load Balancer it uses was configured with a "REDIRECT" to an internal domain. It was this second domain that caused the DNS Error, even though the message references the external domain. I changed the load balancer action from "redirect" to "forward", and now all is well.