ERR_MAKE_WEBHOOK_VALIDATION on Make.com: Make.com Scenario Stops with Webhook Validation Failed. Root cause: Make.com performs a handshake validation when a webhook is first created or re-activated. If the source application does not respond to the validation request with the correct challenge token within the timeout window, Make.com marks the webhook as invalid and stops the scenario. Step 1: Re-run the Webhook Validation. In your Make.com scenario, click the webhook module and select "Re-determine data structure". Then trigger a test event from the source application within 30 seconds. Make.com will capture the payload and complete validation. Step 2: Check Source App Webhook Settings. In the source application (e.g. Shopify, Typeform, GitHub), navigate to the webhook configuration and confirm the Make.com webhook URL is saved correctly. Delete and re-add the webhook if the URL has changed. Step 3: Verify Firewall and IP Allowlisting. Some enterprise environments block outbound webhook calls. Confirm that Make.com IP ranges (available in their documentation) are allowlisted in your firewall or WAF rules. Step 4: Test with Webhook.site. Temporarily point the source app webhook at webhook.site to confirm the payload is being sent correctly. If webhook.site receives the payload but Make.com does not, the issue is with the Make.com URL or scenario activation state.