7 Most Common Online Error Codes & What They Mean

7 Most Common Online Error Codes

Error message details and how to fix them

Updated on December 16, 2022

Error messages are your friend. As unwanted as they are, they provide helpful codes that you can translate into English to understand what the problem might be.

There are lots of error messages you could see while connected to the internet, but below are some of the more common ones most people run into. You might see them when your device isn't connected to the internet at all, or if a web page is down or not responding properly.

Use this list to decipher what's going on, and be sure to follow the links to the full troubleshooting guides for more information.

When you see an error code on a web page, it's considered an HTTP status code. The code is often paired with a phrase (as you'll see below) to provide a bit more context.

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400 Bad Request Error

A 400 Bad Request error can show up in a web browser if you type a URL incorrectly or try accessing a web page that isn't open to the general public.

The number one fix is to double-check the URL to make sure it's been entered correctly. If that doesn't help, use a search engine like Google to find the page, which will more often than not lead you to the correct URL.

How to Fix a 400 Bad Request Error

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403 Forbidden Error

Exclamation error button illustration — D3Damon / Getty Images

A 403 Forbidden error message can be seen if you try to access a web page that needs a username and password. The page isn't allowing access to the public.

This error doesn't mean the page isn't available at all, but just that it's not available to you. It's inaccessible because you're not on the "approved" list of visitors.

You might also see a message about permission access, or it might mention that you're unable to list files in the directory because you're not an authorized user.

For example, a university might not want non-university students accessing its library reference desk, so it requires credentials to limit access. If you don't authenticate with the page, you'll see a 403 Forbidden error.

How to Fix a 403 Forbidden Error

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404 Not Found

404 File not Found — alengo / Getty Images

The 404 Not Found error is seen when the web page you requested can't be found by the web server that it resides on.

This could happen for a variety of reasons, like if the page has been moved without a forwarding address, if the page has been deleted from the server, if an incorrect URL has been entered into the browser address bar, or if the page is temporarily unavailable due to high web traffic or lack of server space.

To fix a 404 error, first check that the page address is valid, and then work your way to the site's home page to see if you can find the page from there or through a search tool on the site.

It's possible the page is completely gone, in which case you might have luck digging it up with a site archival service like Wayback Machine. Google might even be helpful here, through its cache feature.

How to Fix a 404 Page Not Found Error

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Network Connection Refused

yellow network cables hanging from above — jerry john; CC BY-ND 2.0 license

The network connection refused error appears when a website is experiencing lots of unexpected traffic, is under maintenance, or is only accessible by registered users (i.e., you have to log in).

There's usually no need to try fixing this error because it's more often than not a temporary problem. Wait a few minutes (or longer), or try refreshing the page.

It also wouldn't hurt to make sure the URL has been entered accurately. Although possibly a stretch, you could also try reaching the page with a VPN if the connection is refused because of your location.

You might also see this error as network connection refused by the server or network connection timed out.

Can't Connect to the Internet? Try These Tips

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Unable to Locate Host

The word error written on a keyboard — ANDRZEJ WOJCICKI / Getty Images

The error message Unable to Locate Host can show up in several situations: the website is unable to connect with its host server; perhaps because of maintenance or bandwidth issues, the network connection has been lost or interfered with, or the URL is incorrect.

This error is usually temporary. Check the URL for mistakes, hit the refresh button to try again to contact the server, and check the physical network connections to ensure that they're properly attached.

You might also see this described as unable to locate domain, unable to locate network, or unable to locate the address.

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Host Unavailable

Error on computer screen — alengo / Getty Images

The error message Host Unavailable can show up when a site is unable to connect with its server; this could be because it's experiencing unexpectedly heavy traffic, undergoing maintenance, or because it's been taken down.

Like some online error messages, this one is usually not a permanent issue. Refresh the page to try again, clear your cookies, or simply wait a while and try again later.

You might also see this as domain unavailable, network unavailable, or address unavailable.

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503 Service Unavailable

The 503 Service Unavailable error might happen because the connection to the internet has been lost or interfered with, the site has been deleted or moved, or the site is experiencing too much traffic and is temporarily down.

To fix it, start by checking the URL for problems (maybe it was typed incorrectly). Refresh the page a few times and then try rebooting your network hardware.

How to Fix a 503 Service Unavailable Error

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