When a webhook fails

Your endpoint did not answer before the delivery timeout. This is usually a slow handler or a temporary outage.

In Make

Rare: a Custom webhook answers as soon as it receives the call.

In your code

Your handler did not answer within the delivery timeout. Answer 200 first, then do the slow work in the background.

Fix: Retries continue automatically. Make the handler respond quickly (acknowledge first, then do the work).

The request never reached a working HTTP server: the host could not be resolved, refused the connection, or dropped it.

In n8n

A self-hosted instance that is down, restarting or not reachable from the internet.

In your code

The domain does not resolve, the server is down, or it does not accept HTTPS connections on port 443.

Fix: Retries continue automatically. Check that the domain resolves publicly and the server accepts HTTPS.

Your endpoint answered with a redirect. Webhook Scheduler never follows redirects, so a 3xx counts as a failed attempt and is retried like a 5xx, with the same answer each time.

In your code

Usually http to https, a missing or extra trailing slash, or a domain that moved. Use the final URL, the one the redirect points to.

Fix: Use the final URL, the one the redirect points to.

Your endpoint refused the request. Webhook Scheduler removes Authorization and Cookie headers before delivery, so it cannot send those credentials. On Make or n8n, the webhook itself may require authentication.

In n8n

The Webhook node has authentication set (Header Auth, Basic Auth...). Send the header it expects under a name other than Authorization, or turn its authentication off and check the signature in the workflow.

In your code

Your auth middleware runs on the webhook route. Exempt it and verify Webhook-Signature instead.

Fix: Send the secret in a custom header your receiver checks (any name except Authorization or Cookie), turn authentication off on that webhook, or verify the Webhook-Signature header instead, then edit and reschedule.

The request reached your server, but no route exists at this URL. Retrying the same URL would fail the same way, so it was not retried.

In n8n

Workflow 2 is not active, or the URL is the Test URL instead of the Production URL.

In Make

The address is mistyped or belongs to a deleted webhook.

In your code

A typo in the path, or the route is not deployed on that host.

Fix: Check the path for typos and that the route is deployed, then edit and reschedule.

The endpoint says this URL is gone for good. On Make or n8n, that usually means the scenario or its webhook was deleted or turned off. Retrying the same URL would fail the same way, so it was not retried.

In Make

The Custom webhook of scenario 2 was deleted, or the scenario was turned off for good. Copy the address from scenario 2 again.

In n8n

The webhook was removed from the workflow. Copy the Production URL again.

Fix: Copy the webhook address from your scenario again (or check the route is deployed), then edit and reschedule.

Your server received the request but rejected its body or format. The response body below usually says which field is wrong.

In your code

Your validation refused the JSON body. Every delivery is sent with Content-Type: application/json.

Fix: Adjust the JSON payload to what the receiver expects, then edit and reschedule.

The URL exists, but it does not accept this HTTP method. Many pages only accept GET; webhook receivers usually expect POST.

In Make

A Custom webhook accepts POST: check the method of the scheduled webhook.

In n8n

The Webhook node’s HTTP Method must match the method you schedule (POST by default).

Fix: Use the method your receiver expects, or point to its webhook route, then edit and reschedule.

Your server asked to try again later. The delivery is retried with backoff.

In your code

Many webhooks scheduled for the same second hit your rate limit. Spread runAt by a few seconds, or raise the limit for this route.

Fix: No action needed unless every attempt is rate limited; then raise the receiver limit.

Your server failed while handling the request. This is often temporary, such as a deploy or a crash.

In your code

Your handler threw an error or your server was restarting. Your logs at the attempt’s time say which.

Fix: Retries continue automatically. Check your server logs for this request.

The URL resolved to a private, local or otherwise unsafe address, so the request was not sent.

In your code

The URL resolves to a private, local or reserved address. See Target URL rules.

Fix: Use a public HTTPS endpoint, then edit and reschedule.

The JSON payload is larger than the delivery limit, so the request was not sent.

In your code

The JSON body is over 100 KB. Send an ID and let the receiver look up the rest.

Fix: Send a smaller payload (for example an ID your receiver can look up), then edit and reschedule.