Webhook Not Responding to Slack Slash Commands — dispatch_failed Despite Correct Setup

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Hi n8n team,

I’m encountering a critical webhook issue in my n8n Cloud workspace:

Workspace URL: https://visionairy.app.n8n.cloud

:wrench: Issue Summary

Slack slash commands are configured to POST to a production webhook in my workflow. The webhook:

  • Is set to POST
  • Is set to Respond Immediately
  • Returns a valid static JSON body like:

json

CopyEdit

{ "text": "✅ VCI webhook is working." }
  • Has Raw Body turned off
  • Uses no authentication

Despite this, Slack always returns dispatch_failed. I’ve tested:

  • Webhook paths: /vci-db-query, /vci-db-query-test, and others
  • Brand new workflows with only a Webhook node
  • Both production and test URLs
  • Clean re-deploys and saved workflows
  • Valid request URL set inside Slack App config
  • Ensured Slack receives a 200 OK response within 2 seconds

No success — n8n Cloud is not returning a valid response even for isolated minimal workflows.

:paperclip: Additional Notes

  • Slack’s logs confirm it’s POSTing successfully.
  • Executions do show up inside n8n, but the webhook never returns a body.
  • Testing via browser shows:
    {"code":404,"message":"This webhook is not registered for GET requests"} — as expected.
  • Replacing the webhook node, changing workflow, and hardcoding static responses did not solve it.

Can you please investigate why Slack POSTs to production webhooks are not receiving valid responses from n8n Cloud?

Happy to share screenshots or grant support access if needed.

Thanks,
Russ Wright
Founder, VisionAIry