ERR_EMPTY_RESPONSE: What It Means and How to Fix It
An empty response means the server accepted your request and then sent nothing back. Here is what that points at, and how to fix it on both sides.
401 Unauthorized: What It Means and How to Fix It
A 401 means the server wants credentials it did not get, or did not accept. Here is how it differs from a 403 and what to do on both sides.
NET::ERR_CERT_AUTHORITY_INVALID: How to Fix It
This means your browser does not trust whoever issued the site’s certificate. Here is what causes it, what is safe to click, and how to fix your own site.
429 Too Many Requests: What It Means and How to Fix It
A 429 means a server is telling you to slow down. Here is what triggers it, how to get back in as a visitor, and how to stop it happening on your own site.
ERR_CONNECTION_REFUSED: What It Means and How to Fix It
Connection refused means something answered and said no. Here is what that rules out, and seven fixes for visitors and site owners, in order of likelihood.
ERR_ADDRESS_UNREACHABLE: What It Means and How to Fix It
Address unreachable means the route to that server does not go anywhere. Here is what it rules out, and seven fixes for visitors and site owners.
ERR_QUIC_PROTOCOL_ERROR: What It Means and How to Fix It
QUIC is the newer protocol Chrome tries first. When something in the middle blocks it you get this. Here is the one setting that fixes most cases.
ERR_HTTP2_PROTOCOL_ERROR: What It Means and How to Fix It
This means the browser and server fell out of step while speaking HTTP/2. Here is how to tell whose side it is on, and the fixes for each.
ERR_SSL_VERSION_OR_CIPHER_MISMATCH: How to Fix It
This means your browser and the server could not agree on how to encrypt the connection. Here is what causes it, and the fixes for both visitors and owners.
ERR_CONNECTION_RESET: What It Means and How to Fix It
Connection reset means the conversation was cut off partway through. Here is what causes it and eight fixes, starting with the ones that take a minute.