Yes, I’ve seen this before. In most cases it’s due to how Vapi sends the tool payload n8n is strict about the expected HTTP method, headers, and body structure. Make sure the tool is using POST, Content-Type: application/json, and that the webhook node is set to accept raw JSON. Also log the incoming request in n8n to confirm whether Vapi is sending an empty or mismatched body. Happy to help you debug it step by step. @iCreatewebtech