---
title: "ERR_BLOCKED_BY_CLIENT: causes and how to fix it"
description: "The browser itself refused to send the request because an extension — usually an ad or tracker blocker — matched it against a block list. The server was…"
canonical: "https://lemwatch.com/errors/err-blocked-by-client"
source: "https://lemwatch.com"
---

# ERR_BLOCKED_BY_CLIENT: An extension blocked the request

> The browser itself refused to send the request because an extension — usually an ad or tracker blocker — matched it against a block list. The server was never contacted.

## Short answer

 The browser itself refused to send the request because an extension — usually an ad or tracker blocker — matched it against a block list. The server was never contacted.

## What ERR_BLOCKED_BY_CLIENT means

 This is entirely client-side. The request never left the browser. It commonly hits analytics, ad and tracking endpoints, and occasionally first-party paths whose names resemble them.

## Causes and fixes, most likely first

- An ad blocker or privacy extension matched the URL. Test in a private window with extensions disabled to confirm, then allowlist the domain if the request is legitimate.
- A first-party path contains a word matched by a filter list (ads, analytics, track). Rename the path or serve the script from a first-party route that does not match common filter patterns.

## How to stop it happening again

- Avoid filter-bait words in first-party asset paths.
- Never make critical functionality depend on a request that filter lists commonly block.

## Check your own domain

 An external probe fetches the URL with no extensions in the way, proving the resource is served correctly and the block is local.

## Frequently asked questions

### Does ERR_BLOCKED_BY_CLIENT affect SEO?

 No. Crawlers do not run ad blockers. It affects real users with extensions, and only for the specific blocked requests.


## Related

- [All website error codes](https://lemwatch.com/errors)
- [ERR_EMPTY_RESPONSE](https://lemwatch.com/errors/err-empty-response)
- [ERR_CONNECTION_REFUSED](https://lemwatch.com/errors/err-connection-refused)
- [Free Uptime & response check](https://lemwatch.com/tools/website-uptime)
- [ERR_CERT_AUTHORITY_INVALID: The certificate is not issued by a trusted authority](https://lemwatch.com/errors/err-cert-authority-invalid)
- [ERR_BAD_SSL_CLIENT_AUTH_CERT: The client certificate was rejected](https://lemwatch.com/errors/err-bad-ssl-client-auth-cert)
- [Lemwatch pricing](https://lemwatch.com/pricing)