axios Network Error (ERR_NETWORK) (tested)

AxiosError: Network Error with code: 'ERR_NETWORK' means the browser gave axios no HTTP response at all. We triggered seven failure types with axios 1.20.0 in Chromium 153. Four different causes produced the exact same error object. Only the DevTools console showed which one it was.

1. What ERR_NETWORK means

In the browser, axios uses XMLHttpRequest. When the request fails before any HTTP response is readable, XHR fires an error event with status 0. axios turns that into message: 'Network Error', code: 'ERR_NETWORK' and error.response === undefined. The browser does not tell JavaScript why. That is on purpose, so pages cannot probe other networks.

2. Our test setup

A Node HTTPS server served a blank page on https://127.0.0.1:8991. We injected axios.min.js into it and called axios.get() against different targets. For each call we logged error.message, error.code, error.response, error.request.status and the console messages Chromium printed.

try {
  await axios.get(url, opts);
} catch (e) {
  console.log(e.message, e.code, e.response?.status, e.request?.status);
}

3. Results in Chromium 153

Key points:

• The first four rows are identical in JavaScript. You cannot tell CORS from a down server from a typo in the host name by looking at the error object.
• A timeout is not ERR_NETWORK. By default it is ECONNABORTED; the abort is ERR_CANCELED with error.name === 'CanceledError' and axios.isCancel(e) === true.
• 4xx gives ERR_BAD_REQUEST and 5xx gives ERR_BAD_RESPONSE, both with a real error.response. If you see a response, it is not a network error.
• Mixed content is checked before DNS. Our first DNS test used an http:// host from the https page and Chromium reported mixed content, not a DNS failure.

4. Node.js is more specific

In Node.js 24 axios uses the http module, and the real error code comes through:

So if the same call works from Node (or curl) but fails in the browser with Network Error, suspect CORS or mixed content first. There is no CORS in Node.

5. How to find the real cause

1. Open DevTools > Console. The red line next to the failed request names the cause: blocked by CORS policy, Mixed Content, net::ERR_CONNECTION_REFUSED or net::ERR_NAME_NOT_RESOLVED.
2. Open the Network tab. A CORS failure shows a request that reached the server; refused and DNS failures show no response at all.
3. Run the same URL with curl from your machine. If curl gets a response, the server is up and the browser is blocking it.

6. Fixes by cause

• CORS: the API must send Access-Control-Allow-Origin for your page origin (and handle the preflight if you send JSON or custom headers). See CORS error messages explained. Changing axios settings cannot fix this.
• Connection refused: the server is not listening on that host and port. Check the base URL, the port, and that the server binds to the right interface. See ERR_CONNECTION_REFUSED / ECONNREFUSED.
• DNS failure: fix the host name in baseURL or the DNS record.
• Mixed content: use https:// for the API, or a relative URL. See mixed content blocked.
• Timeouts: handle ECONNABORTED (or ETIMEDOUT with clarifyTimeoutError) separately from ERR_NETWORK.

catch (e) {
  if (axios.isCancel(e)) return;               // ERR_CANCELED
  if (e.response) { /* HTTP error: e.response.status */ }
  else if (e.code === 'ECONNABORTED' || e.code === 'ETIMEDOUT') { /* timeout */ }
  else if (e.code === 'ERR_NETWORK') { /* CORS, offline, DNS, refused, mixed content: check console */ }
}

fetch() has the same problem with a different message. See TypeError: Failed to fetch.

Written with AI assistance. Measured on 2026-10-02 with axios 1.20.0 (dist/axios.min.js) in headless Chromium 153 via Playwright, against a local HTTPS Node server, and axios 1.20.0 in Node.js 24.21.0. PlainHeaders is our extension; axios, Chromium and Node.js are free.