Hello,
I’m running the N8N102 Section 2 hands-on exercise (“Building a Webhook-Driven Order Processing System”) and the Webhook Tester goes to a blank white page every time I click “Run Step 1 Tests”. I’ve tried quite extensive debugging and i’m wondering if the issue could be on the tester side, not my webhook (?). Details below.
Environment
- Self-hosted n8n (Registered Community edition) behind a reverse proxy with a valid Let’s Encrypt cert, HTTPS enforced
- Tester page: Webhook Tester - n8n Academy | N8N102
- Browsers tested: Brave (shields down, VPN off) and Safari — same white screen both times
What I’ve already verified
1. My webhook works correctly with curl
Valid order returns 200 and the expected JSON:
curl -i -X POST -H "Content-Type: application/json" -H "X-API-Key: [my API key]" -H "X-Assessment-ID: [my assessment ID]" -d '{"order_id":"ORD-001","customer_id":"CUST-001","total":123}' [my production webhook URL]
→ HTTP/1.1 200 OK → {“status”:“accepted”,“order_id”:“ORD-001”,“message”:“Order received and queued for processing”}
Missing fields returns 400:
curl -i -X POST -H "Content-Type: application/json" -H "X-API-Key: [my API key]" -H "X-Assessment-ID: [my assessment ID]" -d '{"order_id":"ORD-001"}' [my production webhook URL]
→ HTTP/1.1 400 Bad Request → {“status”:“error”,“message”:“Missing required fields: order_id, customer_id, and total are required”}
Missing auth returns 403:
curl -i -X POST -H "Content-Type: application/json" -d '{"order_id":"ORD-001","customer_id":"CUST-001","total":123}' [my production webhook URL]
→ HTTP/1.1 403 Forbidden (WWW-Authenticate: Basic realm=“Webhook”)
2. The tester is reaching my webhook
My n8n Executions tab shows the tester’s “VALIDURL-TEST” requests arriving and succeeding (validated → stored → responded). So the tester’s backend does call my endpoint, and my workflow handles those requests without error.
3. The white screen happens with any webhook
I tested with a random dummy webhook URL (from webhook.site) and the tester white-screens exactly the same way. No checkmarks, no error message, nothing.
4. Network behavior
- The tester page loads fine (HTTP 200)
- When clicking “Run Step 1 Tests”, the page reloads as a GET to the same tester URL
- After that, the result never renders, just a white page
- Console shows no errors; Network tab shows no failed requests
What the tester shows before I click the Run button
- Step 1 tests are greyed out (can’t tick/untick, but I can click “Run Step 1 Tests”)
- No checkmarks ever appear, no error message shown
- Step 2 and Step 3 buttons also remain greyed out
My earlier attempts (for context)
- I originally had my webhook’s Authentication set to “None” and handled auth manually in the workflow. The tester rejected the URL with: “webhook_url authentication is invalid. Please ensure you have configured your webhook authentication.”
- I then switched to native Header Auth on the Webhook node. The validation error disappeared, but the white screen persisted.
- I’ve also verified the Webhook node is set to Authentication: Header Auth and uses my Header Auth credential (header name X-API-Key, academy API key as value).
- The white screen was already occurring before the auth config experiments and has continued through every change I’ve made.
Conclusion
The tester’s backend reaches my webhook (proven via n8n executions). My webhook responds with the correct status codes and bodies (proven via curl). The white screen reproduces with a completely unrelated webhook URL (webhook.site). This leads me to wonder if the bug is in the Webhook Tester tool itself (its frontend failing to render test results?), not in the webhook configuration of users.
Any input and help would be greatly appreciated, thanks!