A 406 means the server will not answer in the form that was asked for. On shared hosting it is usually a firewall rule. Here is how to find it.

Mail that will not send usually has one of six causes. How to read the error, check the settings that matter, and prove where it is failing.

Mail that never arrives in Gmail is usually storage, a filter or a forward. Eight checks in order, and how to prove where the message actually went.

Chrome shows this when a site’s certificate does not check out. What each code means, the six fixes that work, and when you should not click through.

The outbox holds mail that has not left yet. What it is, how it differs from sent items, and how to free a message that will not go.

A 405 means the server knows the page but refuses the way you asked for it. What causes it, what a visitor can do, and the five server side fixes.

Blocking one sender does almost nothing. Here is what actually reduces spam in Gmail, Outlook and Yahoo, and what to do when your address has leaked.

ERR_SSL_PROTOCOL_ERROR means Chrome and the site could not agree on a secure connection. Nine things to check, on your side and on the server side.

A 504 gateway timeout means one server waited for another and gave up. What it means in plain words, and what to try whether the site is yours or not.

Outlook can pull a sent email back, but only in some cases. How to recall a message, and what to do when recall will not work for you.