Is the website down for everyone, or just you?
Most "website down" moments are local. Work through these in order; each one rules out a whole group of causes.
- 1
Check it above.
If our server can reach the site, it is not down for everyone: the problem is between you and the site.
- 2
Open a private window.
If the site loads there, clear cookies and cache for it, or disable extensions one by one, ad blockers first.
- 3
Switch networks.
Try mobile data instead of Wi-Fi (or the reverse). If it works on one, your router, workplace filter or internet provider is blocking it.
- 4
Turn off any VPN.
Some sites block VPN and data-centre addresses, which looks exactly like an outage.
- 5
Flush your DNS.
Windows: ipconfig /flushdns. Mac: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder. Phone: airplane mode on and off.
Why websites go down
- Server overload or crash
- Traffic spikes, a runaway process or a full disk take the server offline. Usually shows as 502, 503 or no answer.
- A bad deployment
- A broken update or configuration change. The most common cause of big outages, including Fastly in 2021 and Cloudflare in 2025.
- DNS problems
- If DNS fails, browsers cannot find the server at all. The October 2025 AWS outage started with a DNS fault.
- Expired domain or SSL certificate
- An expired domain stops resolving; an expired certificate makes browsers block the page with a warning.
- Hosting or cloud provider outage
- When a cloud region or CDN fails, thousands of unrelated websites go down at the same moment.
- Firewall or bot protection
- Rules that are too strict can block real visitors, search engines or whole countries.
- Attacks
- DDoS floods overwhelm a server; a hacked site can be taken offline by the host or flagged by browsers.
Website error messages explained
The exact error tells you who can fix it: you, or only the site owner.
| Error | What it means | What to do |
|---|---|---|
| ERR_NAME_NOT_RESOLVED / DNS_PROBE_FINISHED_NXDOMAIN | The name could not be found in DNS | Check the spelling; if it is right, the domain or its DNS is down |
| ERR_CONNECTION_TIMED_OUT / REFUSED | The server did not answer or refused | Down for everyone if our check fails too |
| NET::ERR_CERT_DATE_INVALID | Expired SSL certificate | The site owner must renew it |
| 403 Forbidden | Access denied for you | Often location, IP or firewall rules |
| 404 Not Found | The page does not exist | The site is up: try its homepage |
| 429 Too Many Requests | Rate limited | Wait a few minutes |
| 500 Internal Server Error | The application crashed | Server-side, usually temporary |
| 502 / 503 / 504 | Gateway, overload or timeout | Server-side, usually temporary |
| 520 to 526 (Cloudflare) | The site's server behind Cloudflare failed | Only the site owner can fix it |
Is it your website? A 10-minute recovery checklist
- Run the check above and read the findings: they point at DNS, the server, the certificate or the firewall.
- DNS: confirm your records and nameservers with our DNS lookup, and that the domain has not expired with a WHOIS lookup.
- Certificate: check expiry and the full chain with the SSL checker.
- Server: check your host's status page, server load and disk space, then the application and web server logs.
- Last change: if you deployed or changed settings recently, roll it back first and investigate second.
- Firewall: if real visitors are blocked, review bot and firewall rules with the HTTP headers tool.
- Hacked? Spam pages, redirects or a browser warning point to a compromise: read how to check if your website is hacked.
ONCE IT IS BACK UP
Check what else is exposed
Outages and hacks often share causes: outdated software, missing security headers, misconfigured servers. A free scan shows them in a minute.
Run a free security scanThe biggest internet outages
When a cloud provider or CDN fails, thousands of unrelated websites go down at once. These are the ones that taught the industry the most.
NOV 18, 2025
Cloudflare: large parts of the web returned errors for about 3 hours
A database permissions change doubled a bot-management file past a hard limit in its proxy. Source: ThousandEyes
OCT 29, 2025
Azure Front Door: Microsoft 365, Xbox, Minecraft and Azure customers hit
A configuration change to Azure infrastructure. Source: ABC7
OCT 20, 2025
AWS us-east-1: thousands of apps and websites down for most of a day
A race condition in DynamoDB DNS automation, then load balancer failures. Source: AWS summary
OCT 4, 2021
Facebook, Instagram and WhatsApp offline for about 6 hours
A network maintenance command withdrew Meta from the internet. Source: Meta Engineering
JUN 8, 2021
Fastly CDN: Reddit, Twitch, news sites and governments down for under an hour
A dormant software bug triggered by one valid customer configuration. Source: Catchpoint
How this checker works
Each check runs from our server: we resolve the name through Cloudflare DNS and find its nameservers, connect and follow up to five redirects (each one re-checked for safety), read the SSL certificate, and recognise answers from common firewalls such as Cloudflare, Akamai, Sucuri, Imperva and Vercel. Each address is looked up once and every connection goes to that checked address, so a site cannot swap in an internal address mid-check. A whole check is limited to 20 seconds, results are shared for a minute, and any one website can be checked at most 30 times an hour.
Limits: we check from one location, so a problem limited to one country or provider may not show. We only check public websites, and never store what you check. Protego is independent and not affiliated with any site listed here. Last reviewed .
Frequently asked questions
How do I check if a website is down for everyone?
Type the address into the checker above. We look it up in DNS, connect from our server, check its SSL certificate and detect bot protection. If it fails from our side too, it is down for everyone. If it works for us but not for you, the problem is your connection, browser or network.
Why does a website work for others but not for me?
Usually because of something between you and the site: a stale DNS cache, a browser extension, a VPN, a work or school filter, your internet provider, or an old cached copy of the page. Try a private window, then mobile data instead of Wi-Fi. If both fail, flush your DNS.
What does "up, but blocks automated checks" mean?
The site's firewall (Cloudflare, Akamai, Sucuri, Vercel and others) answered our automated check with a challenge instead of the page. That is normal for protected sites and almost always means the site is up for people using a normal browser.
What do 502, 503 and 504 errors mean?
All three mean the website's server is in trouble, not your device. 502 Bad Gateway: a proxy got no valid answer from the application. 503 Service Unavailable: the server is overloaded or in maintenance. 504 Gateway Timeout: the application took too long. They are usually temporary.
What are Cloudflare errors 520 to 526?
They mean Cloudflare is working but the website's own server behind it is not. 521: the server refused the connection. 522: it timed out. 523: it is unreachable. 524: it was too slow. 525 and 526: its SSL certificate or handshake failed. Only the site owner can fix them.
Can an expired SSL certificate make a website look down?
Yes. When a certificate expires, browsers show a full-page security warning instead of the site, so most visitors assume it is down even though the server works. Our checker flags expired, untrusted and soon-to-expire certificates.
Do you store the websites I check?
No. We do not save the addresses you check or the results. The result for a page is shared for one minute so many people checking at once do not flood the site, and any one website can be checked at most 30 times an hour.
Can I check sites on my own network, like a router or intranet?
No. For security we only check public websites. Private addresses, internal names and cloud metadata addresses are refused, and so are redirects that lead to them.