Getting Axios 404 Error on Webhook calendar_sarah during suggested slot booking

[faqid80]

Hello everyone,

I am building an AI receptionist. I have integrated a workflow using Retell and n8n. Everything works perfectly during the initial booking flow: if a slot is available, it books smoothly, and if it’s unavailable, the agent correctly informs the user and suggests alternative available slots.

However, the issue occurs when the user tries to book one of those suggested slots. The agent triggers the tool calendar_sarah, but it fails with an Axios 404 error: “The requested webhook ‘calendar_sarah’ is not registered.”

Interestingly, my n8n canvas shows green checkmarks everywhere, and the workflow looks active. I am stuck on this and have tried multiple times. Any guidance on how to fix this webhook registration issue for secondary tool calls would be highly appreciated.

[mark1]

Hey @faqid80 The error message itself gives the answer:

“In test mode, the webhook only works for one call after you click this button.”

This is an n8n test mode limitation — not a Retell issue. When you click “Execute workflow” in n8n, the webhook is only active for a single trigger. After the first booking attempt consumes it, the webhook unregisters itself, causing the 404 on the second tool call.

Fix: Deploy your n8n workflow using the Production webhook URL instead of the test URL. In n8n, switch your webhook node to production mode and activate the workflow via the toggle — this keeps the webhook permanently registered for unlimited calls.

Thank You