DNS server not responding almost always means your device can reach the network but cannot turn names into addresses. The fastest fix, in order: restart the router, flush the DNS cache, and switch to a public resolver like 1.1.1.1 or 8.8.8.8. Nine times out of ten it is the resolver your device was handed - your ISP’s or the router’s - being slow or down, not your computer being broken. Work the list from cheapest to most involved and you will usually find it in the first two steps.
The error is worded to sound like the DNS server is at fault, and often it literally is - just not one you control. The job is to prove whether the problem is your machine, your router, or the resolver, and to route around it.
Table of contents
- Confirm it is DNS and not the whole connection
- Restart the router and modem
- Flush the DNS cache
- Switch to a public resolver
- If it still fails: the deeper checks
- How this fits the rest of the stack
- FAQ
Confirm it is DNS and not the whole connection
Before changing anything, prove the problem is name resolution and not connectivity. Ping an IP address directly:
ping 1.1.1.1If the ping succeeds but websites still fail to load, the network is up and DNS is the culprit - you can reach the internet, you just cannot look up names. If the ping also fails, the problem is your connection, not DNS, and this list is the wrong one.
Then test a name:
nslookup example.com
nslookup example.com 1.1.1.1If the first fails and the second - which forces a specific resolver - succeeds, you have proven your default resolver is the problem and a public one works. That single comparison tells you the fix before you have changed a single setting.
Restart the router and modem
Unglamorous and genuinely the most effective first move. The resolver your whole home uses often runs on the router, and routers accumulate stale state, leak memory, and drop DNS forwarding after long uptime.
Power the router and modem fully off, wait thirty seconds so they clear, then power them back on and let them fully reconnect before testing. This clears the router’s own DNS cache and re-establishes its upstream resolver connection.
If DNS starts working after a reboot and then fails again days later, the router is the weak link - either its firmware or its upstream resolver. That is your cue to stop rebooting it and set your devices to a public resolver directly, so you stop depending on the router’s flaky forwarding.
Flush the DNS cache
Your device caches DNS answers, and a stale or poisoned entry produces exactly this error for one site while others work. Flushing forces fresh lookups:
Windows: ipconfig /flushdns
macOS: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
Linux: sudo systemd-resolve --flush-caches (or resolvectl flush-caches)Run the one for your OS, then retry the site. If a domain that recently moved servers, or one you just changed DNS records for, is failing only on your machine, a stale cache is the likeliest cause and this clears it.
Flushing is safe - the cache just rebuilds from the next lookups. It is worth doing early because it costs nothing and rules out a whole category of one-site-broken problems.
Switch to a public resolver
If your default resolver is slow or down, point your device at a public one that is not:
- Cloudflare:
1.1.1.1and1.0.0.1 - Google:
8.8.8.8and8.8.4.4 - Quad9:
9.9.9.9
Set these in your network adapter’s DNS settings (Windows: adapter properties, IPv4, use the following DNS; macOS: Network, Details, DNS; Linux: your NetworkManager connection or resolved config). Set them on the device rather than the router if you suspect the router.
Public resolvers are run by people whose entire job is keeping DNS up, and they are usually faster and more reliable than an ISP’s default. If switching fixes it instantly, the diagnosis is confirmed: your assigned resolver was the problem. Many people just leave the public resolver in place permanently.
If it still fails: the deeper checks
When the cache flush and a public resolver both fail, the problem is closer to home:
- Reset the network stack (Windows):
netsh winsock resetandnetsh int ip reset, then reboot. This clears corrupted socket and IP state. - Disable a VPN or proxy temporarily. Both intercept DNS, and a misconfigured one produces this exact error.
- Try safe mode with networking or another device on the same network. If another device works, the problem is your machine; if nothing works, it is the router or the line.
- Check the hosts file for a bad manual entry that shadows real DNS.
- Update or roll back the network adapter driver if the failure started after an update.
Work outward from the machine to the router to the line, and swap in a known-good device to bisect the problem. Most DNS failures resolve in the first three steps; these are for the stubborn remainder.
How this fits the rest of the stack
DNS troubleshooting is really the discipline of proving which layer is at fault before you change anything - the same instinct that makes a custom domain on a deployed app painless instead of a guessing game. When you point a domain at a service, knowing how resolution and propagation work is what turns a scary red error into a two-minute wait. The RunxBuild hosting calculator lays out the service, database, storage, and bandwidth as separate line items, and the RunxBuild dashboard is where the team watches deploys, logs, and restarts as they happen.
Useful related references:
- Claude Code MCP Server Setup: The Configuration That Actually Works After the First Restart
- How to Fix a 400 Bad Request: The Part That Is the Server’s Fault, and the Part That Is the Client’s
- npm Error Code 1: The 12 Common Causes, the Debugging Path, and the One Fix That Catches Half of Them
- Services on RunxBuild
FAQ
What does DNS server not responding mean?
It means your device can reach the network but the DNS resolver it was assigned is not answering name lookups, so it cannot turn domain names into IP addresses. Usually the resolver - your ISP’s or your router’s - is slow or down, not your computer being broken.
How do I fix DNS server not responding fastest?
Restart the router and modem, flush your DNS cache, and switch your device to a public resolver like 1.1.1.1 or 8.8.8.8. Most cases resolve in the first two steps. Confirm it is DNS first by pinging 1.1.1.1 - if that works but names do not resolve, it is DNS.
Does changing to Google or Cloudflare DNS fix it?
Often, yes. If your assigned resolver is slow or down, pointing your device at a public resolver like 1.1.1.1 or 8.8.8.8 routes around it. If that fixes the problem instantly, it confirms the diagnosis, and many people leave the public resolver in place permanently.
How do I flush the DNS cache?
On Windows run ipconfig /flushdns; on macOS run sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder; on Linux run sudo resolvectl flush-caches. Flushing forces fresh lookups and clears a stale entry that can break one site while others work.
Why does one website fail with a DNS error but others work?
Usually a stale or bad cache entry for that specific domain, common right after the site changed servers or its DNS records. Flush your DNS cache to force a fresh lookup. If it still fails only in one browser, check that browser’s Secure DNS setting.