A Website Opens on Other Devices but Not One Computer

If a website opens on a phone but not on one computer, the server may still be healthy. Compare the failing computer with a working device to isolate whether the difference is local DNS, browser state, a proxy, security software or the network path.

Capture the exact failure

Record the browser error, hostname and time of the attempt. Check whether other sites fail and whether the affected hostname works in a second browser profile. A certificate warning, DNS error and connection timeout point to different layers.

Compare name resolution and network

On Windows, inspect the DNS answer with Resolve-DnsName example.com, replacing the hostname. Compare it with a known-good device on the same network. Check for an unexpected hosts-file entry, stale VPN route or configured proxy. If the site works over a phone hotspot, that suggests the local network or provider path deserves investigation, but it does not prove which component is at fault.

Do not turn off antivirus or the firewall as a first step. Review the system clock if TLS validation fails; incorrect time can make valid certificates appear not yet valid or expired.

Change one variable at a time

Try a clean browser profile, temporarily disconnect an approved VPN for a controlled test, or compare a second DNS resolver only where policy permits. Note the result after each change and restore the original setting. Clearing all browser data can remove useful sessions and should not be the default diagnostic step.

If the issue persists, provide the hostname, timestamp, error and comparison results to the network or site administrator. A short set of differences is more useful than reporting only that “the site is down.”