Webhook Tester in n8n102 course returns blank white screen during testing

Questions
1

Describe the problem/error/question

I'm trying to use the Webhook Tester: https://learn.app.n8n.cloud/webhook/course/n8n102/webhook-tester but when I set everything up and click "Run Step 1 Tests" all I get back is a white screen. I deactivated my ad blocker (and indeed all of my Chrome extensions) to see if that was the issue, but I'm still getting the same blank white screen. I searched for this issue earlier and someone responded that it was fixed, but I'm still having that issue. Any help in this matter would be greatly appreciated.

What is the error message (if any)?

A blank white screen.

Please share your workflow

(Select the nodes on your canvas and use the keyboard shortcuts CMD+C/CTRL+C and CMD+V/CTRL+V to copy and paste the workflow.)

Share the output returned by the last node

Information on your n8n setup

  • n8n version: 2.33.7
  • Database (default: SQLite): likely SQLite
  • n8n EXECUTIONS_PROCESS setting (default: own, main): default
  • Running n8n via (Docker, npm, n8n cloud, desktop app): n8n Cloud
  • Operating system: ChromeOS
2

@Roy_Dunne Can you show your console when you do this?

Screenshot 2026-08-15 at 7.59.18 AM
Screenshot 2026-08-15 at 7.59.18 AM1045×284 47.8 KB

Right now for me it works fine!

3

Same here. Blank page showed once clicked on the button “Run Step 1 Tests”.
REMARKS:

  1. I hosted my workflow on *.app.n8n.cloud
  2. Tried in Chrome and Edge browsers.
  3. No exception found in “console” tab.
  4. I saw the workflow had been called, but the testing page got blank.
4

Hi @Roy_Dunne Welcome!
The tester blanks when the workflow isn’t published. Step 1 fires three calls in a row, and a test URL only registers one test event for 120 seconds, so the first call lands and the other two go nowhere, leaving the tester page with nothing to render.
Publish the workflow, then take the Production URL from the Webhook node, the one under /webhook/ rather than /webhook-test/, paste that into the tester and run Step 1 again.
See this:

5

It seems to be working now, thanks :+1:

6

I’m still running into the same issue with the N8N102 Webhook Tester.

When I click Run Step 1 Tests, the page turns completely white. I’ve confirmed that:

  • I’m using the Production URL
  • The workflow is published
  • The webhook is being reached successfully
  • The incoming request shows executionMode: production
  • The tester sends the VALIDURL-TEST payload and my workflow responds successfully
  • My RespondSuccess node is configured to return HTTP 200
  • Disabling browser cache in DevTools did not fix it

In Chrome DevTools, the POST request to the webhook-tester endpoint returns 200 OK, but the response has Content-Length: 0, and the Response tab is empty.

Also, each time I run Step 1, I only see one execution in n8n — the VALIDURL-TEST request — rather than the three Step 1 test requests.

This makes it look like the tester is completing the initial webhook validation but then failing before running the actual Step 1 tests.

I’ll try again later in case this is temporary, but wanted to share these details in case the tester is currently having an issue.