How to reconnect a failed Anthropic credential in n8n?

If an Anthropic credential in n8n has “failed” (expired key, wrong key, revoked key, or n8n can no longer authenticate), the fix is simply to open that credential, update the API key, save it, and test it again. In almost all cases, you do not need to rebuild your workflow — just repair the credential itself.

 

What You Actually Do in n8n

 

To reconnect or repair a broken Anthropic credential, you do the following:

• Open Credentials from the left sidebar in n8n.
• Find your Anthropic credential (the name you gave it, like “Anthropic Prod”).
• Click it to open the credential editor.
• Replace the API Key with a valid Anthropic API key from https://console.anthropic.com.
• Click Save.
• Use the built‑in Test button (if available in your n8n version) or manually run a workflow node that uses this credential to confirm it works.

Once you save the credential, every workflow using that credential automatically reconnects — no need to update each node. n8n doesn’t cache the key inside the node; it pulls it live from the credential store.

 

Detailed Explanation (Why It Fails and How the Fix Works)

 

In n8n, an Anthropic credential is just a stored API key. Nodes like Anthropic → Chat use that credential at run time. If the credential “fails,” it usually means:

• The API key was rotated or revoked in Anthropic’s dashboard.
• The key was copied incorrectly or lost formatting.
• Anthropic disabled the key due to inactivity or security rules.
• Your n8n instance lost access to decrypted credentials (usually only when switching environments or restoring backups).

n8n does not automatically refresh or revalidate these keys. When a node tries to call Anthropic with a bad key, you get an authentication error such as “Invalid API Key” or a 401.

The reason the fix is so simple is that credentials in n8n are centralized. Every node that references “Anthropic Prod” dynamically loads the stored key when the workflow runs. So changing the stored key instantly fixes all existing nodes.

 

Production Tips (This Is What Prevents Future Breaks)

 

• Name your credentials clearly — e.g. “Anthropic – Prod – Jan 2026”. It helps when rotating keys.
• Avoid hard‑coding any API keys in expressions. Always use a proper credential object.
• Use an Error Workflow so you get notified if a future credential fails again. Anthropic API failures reliably trigger it.
• If you store secrets externally (Vault, Docker env), verify that n8n still has access after redeploys. Credentials encrypted by n8n require a persistent ENCRYPTION\_KEY.

 

How to Verify the Fix Inside a Workflow

 

You can sanity‑check the repaired credential with a tiny test workflow. For example, add an Execute Workflow trigger and a single Anthropic Chat node:

{
  "model": "claude-3-5-sonnet-latest",
  "messages": [
    { "role": "user", "content": "Ping?" }
  ]
}

If the node runs successfully and returns a JSON message, your credential is fully restored.

 

That’s all it takes: open the credential, paste a valid API key, save, and test. n8n handles the rest automatically across all workflows.