Setup tips
To flush DNS is to clear the website addresses your device has saved, so it looks them up again. It can fix some “This site can’t be reached” errors. Here’s how to flush DNS on Windows, Mac, Chrome and phones, and what to do about other DNS errors.
In short
Your computer and phone keep a DNS cache: a short list of sites they visited and the IP addresses of their servers. It makes sites open faster. But if a site moves to a new server, or a lookup fails once, the saved entry can keep the site from opening. Microsoft says you can flush the cache during DNS troubleshooting to discard such entries.
In Chrome, many DNS problems end on a page that says “This site can’t be reached.” The code under the message tells you more:
| Error | What it means · What to do |
|---|---|
| DNS_ | Your DNS servers work, but they found no site with this name. It may be a typo. Check the address, then flush DNS. |
| ERR_ | The site’s name couldn’t be turned into an IP address. Flush DNS and check your DNS settings. |
| DNS_ | There’s no internet connection. Check Wi-Fi or the cable, then restart the router. |
| DNS_ | The DNS settings are wrong, or the DNS servers are down. Check the DNS addresses in your settings. |
| ERR_ | DNS worked, but the site’s server refused the connection or didn’t answer. Not a DNS problem. Try again later or check your proxy and firewall settings. |
ipconfig /flushdns is the flush DNS command for Windows: it clears the DNS cache of Windows itself. Chrome keeps a DNS cache of its own, so if the site still doesn’t open in Chrome, clear that one too.
Apple also suggests a simpler way: restart the Mac, and it looks up every site again.
Chrome has its own DNS cache, separate from the one in Windows or macOS. To flush the DNS cache in Chrome on a computer:
Phones have no button for this. The simplest fix is to restart the phone.
If Android shows “Private DNS server cannot be accessed”, the phone can’t reach the server set in Private DNS. Check the hostname for typos, or switch to mobile data: some public Wi-Fi networks block encrypted DNS. The Android guide shows where the setting is.
Windows Network Diagnostics may report that the DNS server isn’t responding: your computer gets no answers from it. Work through these steps:
It deletes the website addresses your device has saved. The next time you open a site, the device asks the DNS server again. Passwords, history and cookies stay.
Yes. The only effect is that each site takes a moment longer to open the first time, while its address is looked up again.
Android has no button for it. Restart the phone, and it looks up every site again.
Chrome checked your DNS servers and they work, but they found no site with that name. Check the address for typos. If it’s correct, flush DNS and try again.
It can help when your current DNS server is down. First restart the router and flush DNS. If sites still don’t open, try another DNS service.
It blocks some addresses on purpose, so a blocked site doesn’t open. If you need the site, add it to your allow list. The query log in your account, once you turn it on, shows what was blocked.
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