n8n - 💡(How to fix) Fix HTTP Request node fails with HPE_INVALID_CONSTANT for Standard ERP / HansaWorld REST API, while curl and Node.js work [1 comments, 2 participants]

{
  "errorMessage": "Parse Error: Expected HTTP/, RTSP/ or ICE/",
  "errorDetails": {
    "rawErrorMessage": [
      "Parse Error: Expected HTTP/, RTSP/ or ICE/"
    ],
    "httpCode": "HPE_INVALID_CONSTANT"
  },
  "n8nDetails": {
    "nodeName": "HTTP Request",
    "nodeType": "n8n-nodes-base.httpRequest",
    "nodeVersion": 4.4,
    "itemIndex": 0,
    "time": "25.04.2026, 11:40:43",
    "n8nVersion": "2.17.7 (Cloud)",
    "binaryDataMode": "filesystem"
  }
}
Stack trace:

NodeApiError: Parse Error: Expected HTTP/, RTSP/ or ICE/
    at ExecuteContext.execute (.../n8n-nodes-base/nodes/HttpRequest/V3/HttpRequestV3.node.ts:825:16)
    at processTicksAndRejections (node:internal/process/task_queues:104:5)
    at WorkflowExecute.executeNode (.../n8n-core/src/execution-engine/workflow-execute.ts:1048:9)
    at WorkflowExecute.runNode (.../n8n-core/src/execution-engine/workflow-execute.ts:1239:11)
Please share your workflow/screenshots/recording
Minimal workflow: first, a Code node outputs [{"access_token":"<valid_access_token>","hansa_url":"http://<hansa-host>:10013/api/1/ORVc/<record-id>"}]. Then an HTTP Request node is configured with Method GET, URL http://213.250.128.238:10013/api/1/ORVc/20261513, Authentication None, Send Headers true, Headers Authorization: Bearer {{$json.access_token}}, Accept: text/xml, Connection: close, and Response Format Text. Sensitive data such as the real access token has been removed.

Share the output returned by the last node
n8n HTTP Request node returns no output because it fails with Parse Error: Expected HTTP/, RTSP/ or ICE/.

The same request works with curl:

curl -i \
  -H 'Authorization: Bearer <valid_access_token>' \
  -H 'Accept: text/xml' \
  -H 'Connection: close' \
  'http://<hansa-host>:10013/api/1/ORVc/<record-id>'
curl response:

HTTP/1.1 200
Content-Type: text/xml; charset=UTF-8
Content-Length: 1804
Connection: keep-alive
Response body starts with:

<?xml version='1.0' encoding='UTF-8' standalone='yes'?>
<data sequence='5275983'>
  <ORVc register='ORVc' sequence='5275983' url='/api/1/ORVc/'>
    ...
  </ORVc>
</data>
I also tested the same URL and token using a plain Node.js http.request client outside n8n, and it returns HTTP 200 with the expected headers and body.

Additional context: a broad request to /api/1/ORVc returns a very large XML response, but this issue also happens with the single-record endpoint /api/1/ORVc/. The single-record response is small, around 1804 bytes. HTTPS port for this Standard ERP server is currently not reachable externally, so the test is over plain HTTP port 10013.

Question: could this be an issue with how the HTTP Request node or its underlying HTTP client parses this server’s HTTP response? Is there any workaround in n8n Cloud, or any option to make the HTTP parser more lenient for this request?

Debug info
core
n8nVersion: 2.17.7
platform: docker (cloud)
nodeJsVersion: 24.14.1
nodeEnv: production
database: sqlite
executionMode: regular
concurrency: 5
license: enterprise (sandbox)
storage
success: all
error: all
progress: false
manual: true
binaryMode: filesystem
pruning
enabled: true
maxAge: 168 hours
maxCount: 2500 executions
client
userAgent: mozilla/5.0 (macintosh; intel mac os x 10_15_7) applewebkit/605.1.15 (khtml, like gecko) version/26.3 safari/605.1.15
isTouchDevice: false
Generated at: 2026-04-25T09:41:59.177Z