Why some sites block automated checks, and what we say when that happens

A site that loads perfectly for you can still refuse to answer a checking tool. This is one of the main reasons uptime checkers disagree with each other, and it is why we are careful about the word “down”.

Why sites do this

• Bot protection. Security services look for traffic from data centres and block anything that does not look like a normal person with a normal browser.
• Scraping and abuse. Sites protect their content and prices from copying.
• Rate limits. Too many requests from one address earn a refusal.
• Country or network rules. Some sites only answer certain regions.

What it looks like to us

• A 403, 429 or similar refusal.
• A page that never answers, which shows as a timeout.
• A challenge page instead of the real page.

What we do about it

1. A site is only called down after it returns a server error twice. A refusal is not an error of that kind.
2. Refusals and timeouts are labelled blocked, no answer or inconclusive, never down.
3. If our server cannot reach a site but probes in other countries can, we say so.
4. If we cannot be sure, we say we cannot be sure, and give you a link to open the site yourself.

What you can do

Open the site in your own browser. If it loads, it is up for you. If it does not, try the checklist and look at the site’s official status page or social account, which are the most reliable sources during a large outage.

We do not disguise our checks as a browser. Being open about what we are is part of how we keep our results honest.

Related guides

• How siteupdown.com checks a website, and what the verdicts mean
• What does a 403 Forbidden error mean?
• Why a website can be down for some people and not others

Last updated 2 November 2026. Written by the siteupdown.com team. Spotted a mistake?

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