# Chrome DevTools: net::ERR_FAILED — a request failed with no specific reason (CORS, extension, mixed content or network)

**Code:** `net::ERR_FAILED` · **Category:** Browser · **Seen on:** Chrome, Edge, JavaScript

ERR_FAILED is Chrome’s catch-all for a failed request. In DevTools it very often hides a CORS rejection, an extension, or a blocked mixed-content request.

## Meaning

The console line gives no cause. Look at the Network tab (the Status column and the red request), open the request's headers, and read the console message just above it — a CORS or mixed-content explanation is usually printed separately. Also test with extensions disabled and from `curl`.

## Common causes

- CORS failure (missing Access-Control-Allow-Origin, redirect or error response without CORS headers)
- Mixed content: HTTP resource requested from an HTTPS page
- Browser extension (ad blocker, security tool) cancelling the request
- Server closing the connection or returning an invalid response
- File opened from file:// or a blocked scheme

## Quick fix

1. Read the full console error and the Network tab entry
2. Try an incognito window with extensions disabled
3. Reproduce the request with `curl -v` to see the real server behaviour

## Detailed fix by platform

### JavaScript

1. `fetch(url).catch(e => console.error(e))` — a bare `TypeError: Failed to fetch` is the JS view of ERR_FAILED
2. Add CORS headers on the server for cross-origin calls

### Chrome

1. DevTools → Network → right-click the failed request → Copy → Copy as cURL, and run it in a terminal

## How to diagnose

1. **Console** — Is there a CORS or mixed-content message above?
2. **Extensions** — Fails in incognito?
3. **Server** — Does curl work?

---
Source: [WhatIsMyError](https://whatismyerror.com/errors/browser/net-err-failed)