Your server is running fine. Your app hasn't crashed. But visitors get "This site can't be reached" — and the problem isn't your code at all. It's DNS, the system that translates a domain name into the actual server address, and when it breaks, everything downstream looks broken even though nothing actually is.
Check your DNS records right now
Use our free DNS Lookup Tool to instantly see a domain's A, MX, TXT, NS, and CNAME records — no signup needed.
What each record type actually controls
- A record — points your domain to a specific server IP address. If this is wrong or missing, your site simply doesn't resolve anywhere.
- CNAME — points a subdomain to another domain name instead of directly to an IP (common for things like `www` pointing to your main domain, or third-party services like CDNs).
- MX — controls where email for your domain gets delivered. Broken MX records mean bounced emails, not a broken website — but people often confuse the two when troubleshooting.
- TXT — used for verification (proving domain ownership to services like Google Search Console) and email authentication (SPF, DKIM records that prevent your domain from being spoofed for spam).
- NS — tells the internet which nameservers are authoritative for your domain. If these are wrong, nothing else matters — the rest of your DNS records won't even be found.
Why DNS problems are confusing to diagnose
DNS changes don't take effect instantly worldwide — they propagate gradually as different networks' caches update, which can take anywhere from a few minutes to 48 hours. This means a DNS fix can look like it's "not working" for a while, when it's actually working correctly and just hasn't reached everyone yet. It also means a mistake can take just as long to fully reverse.
DNS is the part of the internet most people never think about, right up until it's the exact reason nothing works.
Common causes worth checking first
- A domain registration or renewal that lapsed
- Nameservers pointed at the wrong provider after a migration
- A typo in an A record IP address after switching hosting providers
- TTL (time-to-live) values set too high, slowing down how fast a fix propagates
DNS issues are exactly the kind of thing that's easy to miss until a customer tells you — unless something is checking on your behalf. PingKeeper monitors your site every 60-300 seconds and alerts you the instant it stops resolving or responding, via Telegram, Slack, or Discord. Free for up to three sites.
Stop finding out about outages from customers.
Free forever for up to 3 monitors — set one up in under a minute.
Start monitoring free