Website online check

A page does not load, the browser shows an error, and you wonder whether the website is offline or whether something is wrong with your own device or connection. A website online check answers that question from the outside. It tests the site from an independent server and tells you whether it is online for everyone. This page explains how to read the result, what the common browser error messages mean, a step-by-step checklist for when a site only fails for you, and what site owners can do to know immediately when their website goes offline.

How the website online check works

The tool sends an ordinary web request to the address you enter, from a server in a German data centre, and follows redirects to the final page. It reports the HTTP status code, the final URL, how long the answer took, the web server software if the server shows it and the IP address the domain resolved to. Because it runs outside your network, your browser, cache, DNS settings, VPN and internet provider play no role.

The result is a snapshot of this moment from one location. Websites can be online in one region and offline in another, but in most cases a site that answers this check is online for nearly everyone.

Reading the result

Status 200 means the site is online and delivered the page. 301 or 302 redirects are followed automatically; the final status counts. 5xx codes mean the server or application has an error, and timeouts or connection errors mean the server did not answer: the site is offline. 404 means the specific page does not exist, while the site may be online; check the homepage. 403 or 429 often mean that a firewall or bot protection blocks automated checks; the site may still work for human visitors.

Online for everyone, but not for you

If the check says online but your browser cannot open the site, the problem is somewhere between you and the website. Work through these steps in order; most problems are solved by one of the first four.

• Check the spelling of the address, including the domain ending
• Reload without cache (Ctrl/Cmd + Shift + R) or open a private window
• Try another browser and disable extensions such as ad blockers
• Switch from Wi-Fi to mobile data, or the other way round
• Turn off VPN, proxy or security software temporarily
• Flush the DNS cache or switch to a public DNS resolver
• Restart the router; check the device date and time for certificate errors
• Ask whether a company or school network blocks the site

What browser error messages tell you

Browsers show specific errors that point to the failing layer. “Server not found” or DNS_PROBE errors mean the domain name could not be translated into an address: a typo, a local DNS problem, or an expired or misconfigured domain. Connection timeouts mean the server did not answer, often because it is overloaded, offline or blocked by a firewall. “Connection refused” means the server answered but no web service runs. Certificate errors mean the HTTPS certificate is invalid or expired, or your device’s clock is wrong. 5xx pages come from the website itself.

Offline for everyone

If the online check also fails, the website is offline or broken for all visitors. Typical reasons are server overload, a failed update, a hosting outage, an expired domain or certificate, or maintenance. As a visitor, you can only wait, check the operator’s social media or status page, or contact them through another channel. Large services usually confirm outages publicly within minutes.

Regional and partial outages

Sometimes a site is online in one country and not in another, because of a CDN problem, a regional network disruption, geo-blocking or DNS changes that have not reached every resolver yet. After a DNS change, it can take from minutes to a day until all resolvers use the new address. If friends abroad can reach the site and you cannot, a regional problem or a block is likely.

Windows   ipconfig /flushdns
macOS     sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
Linux     resolvectl flush-caches
Chrome    chrome://net-internals/#dns → Clear host cache

When only one page or feature is offline

Sometimes the homepage loads but a specific page, the login, the shop or a form does not. Check that exact URL with the tool, not just the domain. A 404 means the page was moved or deleted; a 5xx means the part of the application behind that page fails, for example a payment or search service. Login problems are often caused by cookies: clearing the cookies for that site or using a private window helps more often than you would expect.

Mobile apps and websites

If an app does not work but the website does, the app’s API may be down or the app may need an update. If both fail, the service is probably offline. Mobile networks also use different DNS resolvers and routes than your home Wi-Fi, which is why switching between them is such a useful test.

For site owners: what to check first

If your own site is offline, start with the online check to confirm. Then check your hosting provider’s status page and account for notices about maintenance, unpaid invoices or suspensions. Look at recent changes: updates, new plugins, DNS or certificate changes. Check the error logs. If the domain no longer resolves, check the registration and the DNS records at your registrar.

Keeping your website online

Most outages have avoidable causes. Enable automatic renewal for domains and certificates, test updates on a staging copy, keep resource headroom on the server, keep tested backups and know how to restore them. And monitor the site from outside, so that an outage at night is noticed in minutes rather than when the first customer complains in the morning.

From a one-off check to monitoring

A website online check is a manual snapshot. An uptime monitor performs the same check automatically every few minutes, confirms failures, sends an alert when the site goes offline and an all-clear when it is back, and keeps a history of all outages. For any website that matters to a business, this is the logical next step.

Online monitoring with monitordefend

monitordefend checks your websites every five minutes from Germany, confirms failures with a second attempt and emails you when a site goes offline. Firewall and bot-protection blocks are shown as such instead of counting as downtime. Seven more checkers watch links, sitemap, indexing, traffic, checkout, storage and security signals per site. There are no SMS alerts or public status pages.

Frequently asked questions

How do I check if a website is online?

Enter the address in the check above. It tests the site from an independent server and shows whether it answered and with which status code.

Why does a website work for others but not for me?

Usually because of a local cause: browser cache, DNS cache, extensions, VPN, firewall or your network. Work through the checklist on this page.

What does “server not found” mean?

Your device could not resolve the domain name to an IP address. Check the spelling, flush your DNS cache or try another network.

Why does the check show 403 when the site works in my browser?

Some sites block automated requests with a firewall or bot protection. The site is likely online for human visitors.

How long does it take for a site to come back online?

Most outages on small sites last minutes to hours. Without monitoring, owners often notice late, which extends the downtime.

Can I check if a website is online from another country?

This check runs from Germany. For other regions, use a multi-location test or ask someone there to try.

Why does a site say “offline” for me after a DNS change?

Your resolver may still use the old address. DNS changes can take up to a day to reach all resolvers; flushing your cache or using another resolver helps.

Is the website online check free?

Yes, it is free and needs no sign-up.

Related pages

• Website downtime checker
• How to check site downtime
• Website status test
• DNS checker
• SSL certificate checker
• Uptime monitor: know the moment your website goes down