Quick answer
A DNS error means the computer cannot translate the site name into an IP address, so the page won't load even though the internet connection is active. Most often, turning the network off and on, clearing the DNS cache and changing the DNS server to reliable public addresses helps. If the error persists on all devices, the problem is probably in the router or with the provider.
How to recognize the problem
- Browser shows a message that the server cannot find the address or that DNS is not available
- Some pages open, others don't, or none open
- Internet works in apps that use IP addresses, but sites by name don't
- Error occurs on one device while others on the same network work normally
- After changing WiFi network or VPN, sites stop opening
Most common causes
Temporary DNS server failure
The provider's DNS server or the public server you rely on temporarily does not respond. The error then usually disappears on its own after a few minutes to an hour.
Incorrectly entered DNS in settings
The manually entered DNS address is wrong, the second server is missing, or the address is left over from an old network. The device then doesn't know where to send the query.
Outdated or corrupted DNS cache
The computer remembers previous answers and can keep a wrong record, for example after a site's hosting change. Clearing the cache sends a fresh query.
Problem in the router or with the provider
The router does not forward DNS queries or forwards them incorrectly, and sometimes the fault is on the provider's side. Then the error exists on all devices in the network.
VPN, antivirus or hosts file
A VPN tunnel, security software or a modified hosts file can redirect or block DNS queries. The error then appears only while that tool is active.
Step-by-step fix
- 1
Check if the error exists on other devices
Open the same site on a phone connected to the same WiFi. If the error appears there too, the problem is in the network or provider, so continue with the router. If another device works, the problem is local and you fix it on the computer.
- 2
Turn the network off and on
On a Windows computer, open
Settings > Network & internet > WiFiand turn the connection off and on, or toggle the WiFi switch. On a phone, turn on airplane mode for 10 seconds and turn it off. This renews the connection with the DNS server. - 3
Clear the DNS cache
On a Windows computer, open Command Prompt as administrator and run
ipconfig /flushdns. On a macOS computer, open Terminal and runsudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder, then enter your password. Then reopen the site. - 4
Check DNS addresses on the computer
Open
Settings > Network & internet > WiFi > [your network] > DNS server assignment > Editand check if the setting is automatic. If it's manual, enter1.1.1.1and1.0.0.1as primary and secondary server, save and reopen the page. - 5
Change DNS on the router
Log in to the router administration using the address from the manual, usually
192.168.0.1or192.168.1.1. In the WAN/internet or LAN/DHCP settings section, find the DNS fields and enter1.1.1.1and1.0.0.1, then save and restart the router. This usually applies the change to all devices in the network. If you are in a company with an internal DNS server, do not change this without checking with IT support. - 6
Turn off VPN and security software for testing
If you use a VPN, disconnect and check if the site opens. Temporarily disable antivirus or network protection, then test. If the problem disappears, in that program's settings allow DNS traffic or change the operating mode. After testing, turn protection back on.
- 7
Check the hosts file
On a Windows computer, run Notepad as administrator and open
C:\Windows\System32\drivers\etc\hostsin it, then check if there are entries for the site that doesn't work. Make a copy of the file before changing it. Remove entries only if you are sure you didn't add them yourself. On macOS, the corresponding file is/etc/hosts. - 8
Restart the router and computer
Unplug the router from power for 30 seconds, plug it back in and wait for the connection to establish. Then restart the computer. This clears temporary states and re-fetches DNS addresses from the provider.
If nothing helped
If the error persists on all devices even after restarting the router and changing the DNS server, contact your provider and provide the exact message and the time it occurs. Also check if the site is accessible from another location, for example via mobile data, because the problem might not be on your side. In a company with its own server, check if the internal DNS server is working and if the domain records are correct. As a temporary solution, you can sometimes access the site via IP address, but this often doesn't work due to hosting and HTTPS certificates, doesn't solve the cause and is not recommended for sites with login.
How to prevent it
- Use reliable public DNS servers and enter both primary and secondary
- Don't change DNS addresses manually without need and write down the old values
- Occasionally restart the router and update its firmware
- Turn off VPN when not working and check if it blocks traffic
When to call a professional
If the error exists on all devices in the company, if you have your own DNS server or it appears when logging into internal systems, call IT support to check the records and network equipment.
IT infrastructure maintenance · Servers, networks, backup, security and helpdeskFAQ
Is a DNS error dangerous?
No, it's usually a temporary failure or wrong setting, not an attack. If the error appears on only one site, the problem is probably with that site's hosting.
Why do some sites open and others don't?
DNS cache remembers answers individually, so a wrong or outdated record can affect only some names. Clearing the cache and changing the DNS server usually solves such a case.
Which DNS addresses should I use?
For Cloudflare use `1.1.1.1` and `1.0.0.1`, and for Google `8.8.8.8` and `8.8.4.4`. Enter a pair from the same provider in network or router settings and save the changes.