n8n Workflow Not Running? The 6-Stage Diagnosis Ladder

Description and use

Step‑by‑step diagnosis of non‑running n8n workflows: check activation, trigger registration, logs, credentials, network, and infrastructure.

Problem

A self-hosted n8n workflow stops running without obvious canvas errors.

Outcome

By following the six‑stage ladder, most non‑running workflows are restored with minimal effort.

Workflow

• Check the activation toggle to ensure the workflow is active.
• Verify trigger registration: confirm webhooks point to the production URL and cron schedules survived restarts.
• Inspect the executions log: if executions exist with errors, debug node issues; if none, investigate upstream reachability, scheduler, or queue problems.
• Confirm credentials are present, unexpired, and readable by the executing process, especially in queue mode.
• Probe the network path with curl to detect reverse‑proxy stripping, WAF rules, or bot protection blocking requests.
• If infrastructure issues persist, review worker starvation and registration drift; export the workflow and run the free n8n workflow audit to identify activation traps, environment‑local URLs, or missing retries.

Evidence

When a self-hosted n8n workflow is not running, the debugging hour splits in two: the part where everyone stares at the canvas, and the part where the actual cause — which lives outside the canvas — goes uninvestigated.

Source

Inactive workflows never run. The toggle flips back after a hotfix edit; imports default to inactive; activations unwind when credentials expire upstream.

Source

Webhooks must point at the production URL, not the test URL that dies with your tab.

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Executions present with errors → the trigger fired; your bug lives in the nodes (renamed field, rejected payload). Executions absent → upstream: reachability, scheduler, or queue infrastructure.

Source

The credential works on your machine. Is it present, unexpired, readable by the executing process — which, in queue mode, is not the process you're browsing?

Source

Reverse‑proxies stripping path prefixes, WAF rules dropping POST bodies, bot protection aimed at your legitimate sender — all produce a perfectly Active workflow that receives nothing. Probe from outside with curl.

Source

Worker starvation and registration drift belong to the queue‑mode trap list. And to shrink the next scramble: export the suspect workflow, run the free n8n workflow audit — it flags the three upstream causes (activation traps, environment‑local URLs, missing retries) deterministically, in your browser, nothing uploaded.

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