Website Error Messages, Explained in Plain English

Your website goes down and it does not say "your website is broken." It says something like "500 Internal Server Error" or "503 Service Unavailable," and you are supposed to know what that means. Nobody tells you. So here is the plain English version of the error messages I see most, what each one actually means, and which ones mean drop everything versus which ones can wait until tomorrow.

First, a useful secret. Those numbers are not as mysterious as they look. They come in families. Codes starting with 4 usually mean the visitor asked for something the site could not hand over. Codes starting with 5 usually mean the server itself ran into trouble. That one detail already tells you a lot about where the problem lives.

404: The Page Is Not There

A 404 means the server is working fine, but the page someone asked for does not exist at that address. Maybe the page was deleted, maybe the link has a typo, maybe the site was rebuilt and the old addresses changed. A single 404 on one old link is not an emergency. It is housekeeping.

Where 404s become a real problem is when your important pages start throwing them, or when a redesign launches and half the old links in Google point at pages that are gone. Then visitors and search engines hit dead ends all over your site. The fix is usually redirects, sending each old address to the right new one. Boring work, but it matters.

500: The Server Hit Something It Could Not Handle

The 500 error is the one that scares people, because the whole site often goes down behind it. It means the server tried to run your site and something crashed. It is a category, not a diagnosis, and I wrote a whole post on what a 500 error actually means because the causes range from one bad line in a settings file to a plugin update that broke everything. A 500 on your whole site is an emergency, plain and simple. Your site is down and every visitor is seeing it.

502 and 503: The Server Is Overwhelmed or Resting

A 502 Bad Gateway means one part of the server asked another part for help and got a bad answer, or no answer at all. A 503 Service Unavailable usually means the server is too busy, under maintenance, or out of resources. These two often come and go. The site is down, then it is back, then it is down again.

Intermittent 502 and 503 errors are a hosting conversation more often than a website conversation. Your site has outgrown its plan, or a traffic spike is swamping it, or the host has a problem they have not told you about. If they show up once during a huge traffic day, fine. If they show up every week, something needs to change.

403: You Shall Not Pass

A 403 Forbidden error means the server understood the request and said no. Usually it is a permissions problem: a file or folder is set so the web server is not allowed to read it. Sometimes a security plugin or a hosting firewall is blocking visitors it thinks look suspicious, and sometimes it blocks the site owner too, which is a fun day.

A 403 on one folder or one page is rarely an emergency. A 403 on your whole site is, because to your customers it looks exactly like being down.

The Warnings That Are Not Numbers

Some of the scariest messages have no number at all. The browser warning that your site is "Not Secure" spooks customers even though the site still loads, and I cover the three separate causes in why your site says Not Secure. The "too many redirects" loop locks visitors out completely, and that one gets its own post too, on untangling a redirect loop.

If you want the full list of what I check when a site starts throwing errors, my website error help page walks through it. The short version is this: read the error, decide if it is a page problem or a server problem, and check whether the whole site is affected or just one corner of it. Those three answers sort almost every error into "urgent" or "can wait."

When an error code has you stuck, this is the kind of thing I sort out live on a screen share. You watch the error log, the settings files and the tests, and you see exactly which of these it was and what fixed it, no guessing and no jargon left unexplained.