DNS errors explained

Updated October 30, 2026 · 6 minute read · All guides

DNS is the step that turns a name like yourbakery.com into the address of a server. When it fails, the browser can't even start, so the error looks dramatic. The causes are few, and most are fixed by one person.

What the browser shows

Browser	Message
Chrome, Edge	"This site can't be reached", "server IP address could not be found", DNS_PROBE_FINISHED_NXDOMAIN, DNS_PROBE_POSSIBLE
Safari	"Safari can't find the server"
Firefox	"Hmm. We're having trouble finding that site."

NXDOMAIN means "non-existent domain": the name was looked up and nobody has it. The other messages mean the lookup failed or found no address.

How the lookup works, in one paragraph

Your device asks a resolver (your provider's, or a public one like 1.1.1.1). The resolver asks the registry for your domain's ending (.com) which nameservers hold the domain's records; it asks those nameservers for the address record (an A record for IPv4, AAAA for IPv6, or a CNAME pointing at another name); it hands the address back. Every answer is cached for a while, set by the record's TTL, usually between five minutes and a day. That cache is why a change takes time to show everywhere, and why one person can see the old site while another sees the new one.

The five reasons it fails

1. A typo

yourbakery.co, yourbakery.com.com, a missing letter. Check the address bar before anything else. The checker tells you whether the exact name you typed exists.

2. The domain expired

The most common cause for a small business. Domains are rented by the year. When the renewal fails, the registrar removes the nameservers and the name stops resolving, email included. Log in at the registrar, check the expiry date, renew. The name usually works again within an hour or two. After the grace period (often 30 to 45 days) it goes to auction or back on sale.

3. The nameservers changed

The domain is active but points at nameservers that don't have its records: a host you left, a Cloudflare account that was closed, a setting someone changed. At the registrar, compare the nameservers with what your current host says they should be.

4. The address record is missing

The nameservers are right but there's no A, AAAA or CNAME record for the name you typed. The classic small-business version: www.yourbakery.com works and yourbakery.com doesn't, or the other way round. The checker tests both. Add the missing record in the DNS panel, copying the value from the one that works, or ask the host.

5. Stale cache on the visitor's side

The site moved and the visitor's device or provider still holds the old answer. The site is fine for everyone else. Flush the cache or wait; the is it me guide has the commands.

If you're the visitor

• Check the spelling. Try with and without www.
• Run the checker. Red at step 1 means the domain itself is gone or broken; there's nothing you can do but contact the business another way.
• Green means the problem is your cache or your provider's. Switch to mobile data, flush the DNS cache, or set your device's DNS to 1.1.1.1 or 8.8.8.8.

If it's your domain

1. Log in at the registrar. Confirm the domain is active and not expired. Turn on auto-renew and check the card on file.
2. Check the nameservers match what your host or DNS provider gave you.
3. In the DNS panel, confirm an A record (or CNAME) exists for both the bare name and www, pointing at the host.
4. Wait. Changes show within the TTL, typically under an hour; a renewal can take longer.
5. Check again from outside with the checker; it doesn't cache, so it shows the real state.