"This site can't be reached": browser connection errors explained and fixed
"This site can't be reached." "Hmm. We're having trouble finding that site." "Your connection is not private." Browser error pages all look alike, but the small code underneath, such as DNS_PROBE_FINISHED_NXDOMAIN or ERR_CONNECTION_TIMED_OUT, tells you exactly where the connection broke. Here's what each common error means, whether the problem is yours or the website's, and how to fix it.
First: is it the website, or you?
Before trying any fix, paste the address into CheckIfSiteDown. We test the site from our own servers, outside your network:
- Down for us too: the website itself is broken. None of the fixes below will help; wait for the owners to repair it.
- Up for us: the site works, and something between you and it is failing. Find your error below.
Why there are so many different errors
Opening a web page happens in four quick steps, and each one has its own errors. Your browser finds the address (a DNS lookup turns the name into a numeric IP address), connects to that server, secures the connection with the site's HTTPS certificate, and finally loads the page. The error tells you which step failed, and that points straight to the fix.
Step 1 errors: the address can't be found (DNS)
| Error | What it means |
|---|---|
DNS_PROBE_FINISHED_NXDOMAIN | Chrome and Edge: the domain name doesn't exist, as far as your DNS server knows. "NXDOMAIN" means "non-existent domain". |
ERR_NAME_NOT_RESOLVED | The name couldn't be turned into an address. Same family as NXDOMAIN. |
DNS_PROBE_FINISHED_NO_INTERNET | The lookup failed because your device isn't online at all. |
DNS_PROBE_FINISHED_BAD_CONFIG | Your device's DNS settings are wrong or unreachable. |
| Firefox: "Hmm. We're having trouble finding that site." Safari: "Safari can't find the server." | The same DNS failure, in those browsers' words. |
How to fix it:
- Check the spelling of the address, including the ending (.com, .co.za, .net). A typo is the most common cause of NXDOMAIN.
- Check the site on CheckIfSiteDown. If we can't find it either, the domain may have expired or its owner broke its DNS settings.
- Clear your DNS cache so your device asks again. On Windows run
ipconfig /flushdns; the full list for every system is in our troubleshooting checklist. - Switch to a public DNS server such as Cloudflare (
1.1.1.1) or Google (8.8.8.8). If the site loads after that, your internet provider's DNS was the problem. Our guide on how to change your DNS server takes about two minutes. - Turn off any VPN, proxy or "secure DNS" add-on briefly, in case it's the part that's failing.
Step 2 errors: the server won't connect
| Error | What it means |
|---|---|
ERR_CONNECTION_TIMED_OUT | Your browser knocked and nobody answered in time. The server may be down or overloaded, or a firewall is silently dropping your traffic. |
ERR_CONNECTION_REFUSED | The server's address answered, but nothing is accepting web connections there. Often a server that's down, or a wrong proxy setting on your device. |
ERR_CONNECTION_RESET | The connection started, then got cut. Commonly caused by firewalls, antivirus "web shields" or network filters on school, work and public Wi-Fi. |
ERR_CONNECTION_CLOSED / ERR_EMPTY_RESPONSE | The server hung up without sending anything. Usually a struggling server, sometimes a filter. |
ERR_ADDRESS_UNREACHABLE | There's no route to that address from your network. Often a router or provider problem. |
ERR_INTERNET_DISCONNECTED / ERR_NETWORK_CHANGED | Your own connection dropped or switched (for example from Wi-Fi to mobile data) mid-load. Just reload. |
How to fix it:
- Check the site on CheckIfSiteDown. Timeouts and refusals are the classic signs of a real outage. If we also see it as down, wait.
- Try another network. If the site loads on mobile data but not on Wi-Fi, the Wi-Fi network is blocking or mis-routing it. That's very common on school, work and public Wi-Fi.
- Restart your router by unplugging it for 30 seconds.
- Check proxy settings. On Windows, look under Settings > Network & internet > Proxy; on a Mac, System Settings > Network > your connection > Details > Proxies. Unless your employer set one up, these should be off.
- Temporarily pause your antivirus web protection or firewall to see if it's blocking the site, then turn it back on.
Step 3 errors: the secure connection fails
These usually appear as a full-page warning, "Your connection is not private" in Chrome or "Warning: Potential Security Risk Ahead" in Firefox, with a code underneath:
| Error | What it means |
|---|---|
NET::ERR_CERT_DATE_INVALID | The site's certificate has expired, or your device's date and time are wrong. Check your clock first: it's the more common cause. |
NET::ERR_CERT_COMMON_NAME_INVALID | The certificate belongs to a different name than the one you typed. Try the address with or without www. |
NET::ERR_CERT_AUTHORITY_INVALID | The certificate isn't from a recognised authority. Public Wi-Fi login pages and some workplace networks cause this by intercepting connections. |
ERR_SSL_PROTOCOL_ERROR / ERR_SSL_VERSION_OR_CIPHER_MISMATCH | Your browser and the server can't agree on how to encrypt. Usually a server setup problem, or very outdated software on your side. |
How to fix it: set your device's date, time and time zone to automatic; update your browser and operating system; and if you're on hotel or café Wi-Fi, open any plain website first so the network's login page can appear. Don't click "proceed anyway" on banking, shopping or login pages: the warning exists to stop someone reading what you send.
Step 4 errors: the page itself won't load
ERR_TOO_MANY_REDIRECTS("This page isn't working: redirected you too many times"): the site keeps sending you in a circle. Clearing that site's cookies fixes it surprisingly often. If not, the site's setup is broken.HTTP ERROR 500,502,503,504: the server answered, but with an error. These are the website's problem. Our HTTP status codes guide explains each one.- A Cloudflare page with error 520 to 530: the website's own server behind Cloudflare is failing. Also the site's problem, so just wait.
ERR_BLOCKED_BY_CLIENT: something in your own browser, usually an ad blocker or privacy extension, blocked part of the page. Pause it for that site.ERR_BLOCKED_BY_ADMINISTRATOR: your organisation's policy blocks the site on this device.
The site is up, but the error won't go away
If the site checks out as Up, loads on mobile data or for friends, and you've worked through the fixes above, it's probably blocked for your network, internet provider or country, rather than broken. Signs include ERR_CONNECTION_RESET on only one network, a block page with your provider's or organisation's name, or a "not available in your region" message. Our guide Website up but blocked for you? explains what to do next.
The short version
NXDOMAIN and "name not resolved": an address-book (DNS) problem, so check the spelling and try a public DNS server. Timeouts and refusals: check whether the site is down; if it isn't, try another network. Certificate errors: fix your clock and don't click through on sensitive sites. 5xx and 52x codes: the website is broken, so wait. When in doubt, run a check: it tells you in a few seconds whose problem it is.