Fix n8n HTTP Request 401 Error: OAuth2 Token Refresh Guide

Expired OAuth2 tokens cause HTTP Request nodes in n8n to return 401 Unauthorized and halt workflows.

Why the 401 Happens

n8n stores the access token until the API returns a 401, then it never automatically requests a new one.

Step‑by‑Step Token Refresh Setup

1️⃣ Create or edit an OAuth2 credential for the service.

1. Open Credentials → New Credential → OAuth2 API.
2. Enter Client ID, Client Secret, and the Authorize URL/Access Token URL provided by the API.
3. Enable Refresh Token support and set Scope if required.
4. Save the credential.

2️⃣ Add a Set node before the failing HTTP Request to force a token refresh.

{
  "operation": "refresh",
  "credential": "{{ $credentials.myOAuth2 }}"
}

3️⃣ Connect the Set node to the HTTP Request node and enable Authentication → OAuth2 using the same credential.

Copy This Configuration

Credential JSON (export)

{
  "nodes": [
    {
      "type": "n8n-nodes-base.set",
      "parameters": { "operation": "refresh" },
      "name": "Refresh Token",
      "typeVersion": 1,
      "position": [250,300]
    },
    {
      "type": "n8n-nodes-base.httpRequest",
      "parameters": {
        "url": "https://api.example.com/resource",
        "method": "GET",
        "authentication": "oAuth2",
        "credential": "MyOAuth2"
      },
      "name": "API Call",
      "typeVersion": 1,
      "position": [500,300]
    }
  ]
}

Verify the Refresh Worked

After running the workflow, open the execution log and look for a line like "Access token refreshed successfully".

If the log still shows 401, double‑check the Refresh Token URL and ensure the API grants refresh rights.

Common Pitfalls

• Missing grant_type=refresh_token in the token request body.
• Using a credential scoped to a single user instead of the application.
• Expired refresh token – generate a new one via the OAuth consent screen.

FAQ

How do I know if my token is expired?

n8n logs a warning when it receives a 401; you can also inspect the expires_at field in the credential data.

Can I refresh tokens for multiple APIs in one workflow?

Yes, create separate OAuth2 credentials for each API and place a dedicated Refresh node before each request.

What if the API returns 403 after refresh?

403 indicates insufficient scopes; add the required scopes in the credential and re‑authenticate.

Do I need to restart n8n after changing credentials?

No, saved credentials take effect on the next node execution immediately.

Is there a way to auto‑retry after a 401?

Enable Retry on Failure in the node settings and set the retry count to 2‑3.

Bottom Line

Adding a simple Refresh Token node before your HTTP Request ensures n8n always has a valid OAuth2 token, eliminating 401 workflow failures.

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