---
title: "brew install or npm install fails with network errors on Mac · Kilobat Guides"
url: "https://kilobat.app/guides/homebrew-npm-download-fails"
description: "Find why brew install or npm install stops with timeouts, proxy or certificate errors, and set the proxy, mirror or certificate that your network needs."
---

Developers

# Homebrew or npm downloads fail on a Mac

Homebrew downloads with curl and Git. npm downloads from its registry. Each tool reads its own proxy and certificate settings.

Applies to: Current Homebrew and npm on all current macOS versions. · Checked: 29 October 2026

## Symptoms

- `brew install` stops with “curl: (28) … timed out” or “Failed to download resource”.
- `npm install` stops with ETIMEDOUT, ECONNRESET or a certificate error.
- Downloads fail on a company network or VPN only.
- Downloads start and then stop on a slow connection.

## Likely causes

- **A proxy that the tool does not know.** Homebrew uses `http_proxy`, `https_proxy` and `all_proxy`. npm uses its `proxy` and `https-proxy` settings or the same variables.
- **TLS inspection.** A company proxy signs traffic with its own certificate. See [Corporate proxy certificates break Terminal tools on a Mac](https://kilobat.app/guides/corporate-proxy-certificates).
- **A wrong npm registry.** An old `registry` setting can point to a server that you cannot reach.
- **A slow or metered connection.** Large downloads can time out on a weak Wi-Fi or a hotspot.

## How to check

1. Let Homebrew check your system.

   ```
   brew doctor
   ```
2. Show the Homebrew and system configuration.

   ```
   brew config
   ```
3. Show npm's registry and proxy settings.

   ```
   npm config get registry
   npm config get proxy
   npm config get https-proxy
   ```
4. Ask the npm registry for a reply.

   ```
   npm ping
   ```
5. Test the download host directly with curl.

   ```
   curl -v -o /dev/null https://formulae.brew.sh/api/formula.json
   ```

## How to fix it

1. For Homebrew behind a proxy, set the proxy variable in the same shell.

   ```
   export https_proxy=http://proxy.example.com:8080
   ```
2. For npm behind a proxy, set the npm proxy.

   ```
   npm config set https-proxy http://proxy.example.com:8080
   ```
3. Remove an old npm registry setting so npm uses its default.

   ```
   npm config delete registry
   ```
4. Let Homebrew try a failed download more times.

   ```
   export HOMEBREW_CURL_RETRIES=5
   ```
5. If your company uses a mirror, set it. Homebrew uses `HOMEBREW_BOTTLE_DOMAIN` and `HOMEBREW_API_DOMAIN` for mirrors.
6. For certificate errors, add the company root certificate. See [Corporate proxy certificates break Terminal tools on a Mac](https://kilobat.app/guides/corporate-proxy-certificates).

## With Kilobat

1. Before a big install, check whether the network is metered, on a VPN or slow.

   ```
   kilobat conditions
   ```
2. Find the layer that stops the download host. Add `--app` to use the proxy variables of that process.

   ```
   kilobat why https://ghcr.io/v2/homebrew/core --app process:curl
   ```
3. Keep the Mac awake while the install runs.

   ```
   kilobat awake -- brew upgrade
   ```
4. These commands are free. See [Check the network before a big download in an agent](https://kilobat.app/guides/recipes/check-network-before-download).

## Questions

**Does Homebrew use the System Settings proxy?**

Homebrew's documentation lists proxy variables for curl, Git and Subversion. Set `https_proxy` in your shell.

**How long does npm wait?**

npm's documentation gives a default `fetch-timeout` of 300000 ms, five minutes, and 2 `fetch-retries`.

## Sources

- [Homebrew Docs: Manpage, environment variables](https://docs.brew.sh/Manpage)
- [npm Docs: config](https://docs.npmjs.com/cli/v11/using-npm/config)
- curl(1), man page installed with macOS 27.2

Sources checked on 29 October 2026. Man pages are the ones installed with macOS; open one with `man <name>` in Terminal.

## Related guides

- [Corporate proxy certificates break Terminal tools on a Mac](https://kilobat.app/guides/corporate-proxy-certificates): Some company networks inspect HTTPS traffic.
- [Proxy settings stop apps from connecting on a Mac](https://kilobat.app/guides/proxy-settings-breaking-apps): A proxy setting sends traffic through another server.
- [Check the network before a big download in an agent](https://kilobat.app/guides/recipes/check-network-before-download): An agent can ask Kilobat if now is a good time for a large transfer.
- [SSH and Git time out on a Mac](https://kilobat.app/guides/ssh-git-timeouts): SSH and Git need a working TCP connection to the server.
- [“npm error code ETIMEDOUT” on Mac](https://kilobat.app/guides/npm-etimedout): ETIMEDOUT means that the other side did not answer in time.