If a site will not load for you, this test tells you whether it answers from a different network. It follows redirects, reports each status code and timing, and lists the response headers including the six security headers auditors look for.
Table of Contents
Reading the status
2xx and 3xx mean the site is up. 5xx means the server responded with an error (often PHP or database trouble), 403 can mean a firewall is blocking data-center traffic, and “no response” usually means DNS, a firewall or the server itself is down.
If the site is up here but down for you, flush your local DNS cache, try another network, or check whether your IP is blocked by the server’s firewall (CSF, Imunify360 or a CDN WAF).
Website down checker at a glance
How to use this tool
- Enter the site address, for example
example.comor a full URL with a path. Without a scheme the check starts athttps://. - Press Check website. Our server looks up the domain, sends a GET request and follows up to five redirects, waiting up to 12 seconds for each response.
- Read the status first. If it says UP, the server is answering and the problem is between you and the site. If not, the request chain shows at which step it failed.
- Run it again after a fix: this check is never cached, so every run is a fresh request.
If the certificate is not trusted, the checker retries without verifying it and adds a note, so you still learn whether the site itself answers. Requests come from a data-centre IP with the user agent srvScripts-Uptime/1.0; a firewall that blocks such traffic will make a healthy site look down here.
How to read the results
| Row | What it means |
|---|---|
| Status | UP — responding normally when the final response is 2xx or 3xx. Responding with an error (code) when the server answered with 4xx or 5xx. DOWN — no response from our server when DNS failed or no connection could be made. |
| Total time | All hops together, measured from our server. Amber above 3 seconds. |
| Server | The Server header of the final response, for example Apache, nginx, LiteSpeed or cloudflare. It tells you which layer answered. |
| Security headers | How many of six common security headers the final page sends. Green from 5, amber from 3. The security headers checker grades them properly. |
| Request chain | One row per request: the URL, the status line (for example 301 Moved Permanently) and the time and IP address. A failed step shows the error, such as DNS: host does not resolve or the connection error. |
What each status code tells you
| Code | Meaning | Where to look |
|---|---|---|
| 200, 301, 302 | The site is up. Redirects are followed to the final page. | If it fails only for you, your DNS, network or a firewall block on your IP. |
| 401 | Password protection (HTTP authentication) is on. | Directory privacy settings or an .htpasswd rule. |
| 403 | The server refused the request. | File permissions, an .htaccess deny rule, or a WAF blocking our request. |
| 404 | The server is up but that path does not exist. | The URL, or a missing index file for the document root. |
| 429 | Too many requests: rate limiting. | CDN or WAF rate rules. |
| 500 | The application crashed. | PHP fatal errors and .htaccess syntax errors in the web server error log. |
| 502, 504 | A proxy (nginx, a load balancer) got no valid or no timely answer from the backend. | PHP-FPM or the backend web server: stopped, overloaded or too slow. |
| 503 | Service unavailable: maintenance mode or no free workers. | PHP-FPM pool limits, a maintenance file, or the backend being restarted. |
| 508 | Resource limit reached on a CloudLinux account. | The account’s CPU, process or entry-process limits. |
| 520 to 526 | Cloudflare could not get a proper answer from your origin server. | The origin server: down (521), timing out (522, 524) or with an SSL problem (525, 526). |
| No response | DNS failed, the connection was refused, or nothing answered within 12 seconds. | DNS records, the server, its firewall, or the network. |
Common problems and how to fix them
The site is UP here but will not load for you
Clear your local DNS cache, then try a different network such as mobile data. If it loads on the other network, your IP is probably blocked by the server firewall after failed logins.
ipconfig /flushdns # Windows
sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder # macOS
resolvectl flush-caches # Linux with systemd-resolvedOn a server running CSF, search for and remove the block (use your own public IP, shown by the what is my IP tool):
csf -g 203.0.113.10
csf -dr 203.0.113.10 # remove a permanent deny
csf -tr 203.0.113.10 # remove a temporary blockMore firewall commands are in the CSF commands cheat sheet; for Imunify360, see whitelisting an IP in Imunify360.
“DNS: host does not resolve”
The domain has no A or AAAA record that our resolver can find. Typical causes: the domain expired, the name servers were changed to a provider that does not have the zone, or the record was deleted. Check the records and the name servers:
dig +short A example.com
dig +short NS example.comIf the NS records are empty, check the registration with the WHOIS lookup.
500 Internal Server Error
The web server log names the cause. On cPanel the Apache log is /etc/apache2/logs/error_log (also reachable as /usr/local/apache/logs/error_log), on DirectAdmin /var/log/httpd/error_log, on LiteSpeed /usr/local/lsws/logs/error.log and on nginx /var/log/nginx/error.log. A PHP fatal error after a plugin or PHP version update and an invalid line in .htaccess are the two most common finds.
tail -n 50 /etc/apache2/logs/error_log | grep -i example.com502, 503 or 504
The front end is up but the PHP or application backend is not keeping up. Check whether PHP-FPM is running and whether its pool hit pm.max_children; a slow database or an external API call that hangs can also exhaust the workers. See cPanel PHP-FPM tuning and, on DirectAdmin, 503 PHP-FPM errors.
508 Resource Limit Is Reached
A CloudLinux account hit its limits, most often entry processes from a traffic spike or a bot crawl. The account’s resource usage page shows which limit; the fixes are in 508 Resource Limit Is Reached.
Cloudflare 521, 522 or 525
Cloudflare is up but cannot use your origin: the web server is down or blocks Cloudflare’s IPs (521), the connection times out (522), or the SSL handshake fails (525). Work through Cloudflare 521, 522 and 525 on cPanel.
403 here, but the site works in a browser
A WAF or bot filter is blocking requests from data centres or from non-browser user agents: Cloudflare bot settings, Imunify360, ModSecurity rules or a security plugin. That is a choice rather than an outage, but it also blocks uptime monitors and some crawlers, so allow known monitoring services if you rely on them.
Official documentation: AlmaLinux wiki, Linux man pages.
Related guides: Copy Fail, Dirty Frag and Fragnesia: mitigating the 2026 Linux privilege-escalation trio without a reboot · Installing Sentinel Firewall as a drop-in CSF replacement on Ubuntu 24.04 and Debian 13 · Replacing CSF with firewalld + fail2ban on AlmaLinux 9/10, step by step.
Frequently asked questions
Is the site down for everyone or just me?
If this check shows the site up, the problem is between you and the server — local DNS, your ISP, or a firewall blocking your IP.
Which security headers matter most?
Strict-Transport-Security, Content-Security-Policy and X-Content-Type-Options give the most protection; Referrer-Policy, X-Frame-Options (or CSP frame-ancestors) and Permissions-Policy complete the set.
Does this check from multiple locations?
It checks from our server. For multi-region monitoring use an uptime service; for DNS differences by region use the DNS propagation checker.
Why does the checker say UP when my site shows an error page?
The check goes by the HTTP status code. Some applications show an error or maintenance message with a 200 status, which looks healthy to any monitor. Make error pages return a 5xx code so monitors notice.
Does a redirect count as up?
Yes. The checker follows up to five redirects and judges the final response; a site that redirects to a working page is up.
What response time is too slow?
The checker marks a total above 3 seconds in amber. For a home page, aim for well under a second for the first response from the server.
How do I get told when my site goes down?
Add it to the free uptime, SSL and blacklist monitor, which emails you when a check fails. This page only runs a check when you ask.
Can this check a site that is only on my local network?
No. Addresses that point to private or reserved networks are refused, because our server cannot and should not reach them.
Why is the site down right after I changed DNS?
Resolvers may still cache the old records until their TTL expires. Check the new records with the DNS propagation checker; until it shows the new IP everywhere, some visitors reach the old server.