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Common Browser Network Error Codes, Explained

Chromium-based browsers like Chrome and Edge show a specific error code whenever a page fails to load β€” here is what the most common ones mean.

ERR_CONNECTION_REFUSED

The target server actively rejected the connection attempt, usually because nothing is listening on that port, a firewall is blocking it, or the server is down entirely.

ERR_CONNECTION_TIMED_OUT

The browser never got any response at all within the expected time, which usually points to a network routing problem, an overloaded server, or a firewall silently dropping the request instead of rejecting it.

DNS_PROBE_FINISHED_NXDOMAIN

The domain name could not be resolved to any IP address at all, typically because the domain does not exist, was mistyped, or its DNS records were never set up or have expired.

ERR_SSL_PROTOCOL_ERROR

The browser and server could not agree on how to establish a secure HTTPS connection, often due to a misconfigured certificate, an outdated TLS version on the server, or a device clock that is set incorrectly.

NET::ERR_CERT_AUTHORITY_INVALID

The site's SSL certificate was not issued by a certificate authority the browser trusts, commonly seen with self-signed certificates on internal or development servers.

ERR_NAME_NOT_RESOLVED

A broader DNS failure than NXDOMAIN β€” the browser could not complete the lookup process at all, which can point to a problem with the DNS server itself rather than the domain.

ERR_TOO_MANY_REDIRECTS

The site is caught in a redirect loop, often caused by conflicting HTTPS/HTTP redirect rules on the server or a browser cookie that is stuck in a bad state.

The error code tells you which layer failed

Connection-level errors (like ERR_CONNECTION_REFUSED) mean the browser reached the network but not the server; DNS errors (like NXDOMAIN) mean it never even found an address to connect to; SSL/certificate errors mean it found the server but could not verify or encrypt the connection safely. Reading the prefix narrows down where to start troubleshooting.

Most of these are not your device malfunctioning

A large share of these errors originate on the server or network side rather than the visitor's computer β€” a site that is down, a misconfigured certificate, or an expired domain will produce the same error for every visitor, not just one person's browser.

Frequently Asked Questions

Why do Chrome and Firefox show different error messages for the same problem?

Each browser engine defines its own set of error codes and wording. Chromium-based browsers (Chrome, Edge, Brave) share the ERR_ and NET::ERR_ naming convention, while Firefox uses its own separate set of error messages for equivalent failures.

Can clearing my browser cache fix these errors?

Sometimes, particularly for stale redirect loops or cached SSL state, but it will not help for errors caused by a genuinely broken server, an expired domain, or a real DNS misconfiguration.