“Content is king!” – shoots the crowd.

But if your website can’t even load and throws errors, nothing else matters. Your keyword research, your deep and beautifully formatted guides, your hard-earned backlinks…

If the server can’t send the page content to the user’s browsers, everything goes in vain.

So, yeah, content is really the king, but only if your website always works.

What is a 5xx Server Error?

Your site is a complex software that runs on a computer called a “server.” So when a user tries to open it, they type in your domain name, and their browser connects to your server, which instructs the complex software to generate an “HTML document” as a response.

This process can be interrupted by several types of errors.

The most common of them are 4xx Client Errors and 5xx Server Errors. For example, if the user wants to sign up and enter an invalid email, that will result in a 400 Bad Request response.

So basically, the client-side errors are generated by the user and their browser. On the other hand, server errors occur because of a problem on the server.

For illustration, let’s say that the user wants to search for something, but there is a bug in the search functionality that occurs when a small set of special symbols are typed in. In that case, the server won’t finish its job and will throw a 500 Internal Server Error.

How To Find Server Errors?

Ok, you know what they are, but how do you discover Server Errors (5xx)?

Most often, you discover them by accident. You update your WordPress theme or plugins, and suddenly you no more can open any web page.

They show an error…

Other times those errors already exist. They don’t affect everything, but just specific web pages you don’t know in advance. If you don’t try to open them, you won’t discover that they actually don’t work.

So it’s a good idea to check your website for such errors regularly.

There are several ways you can do it…

Checking For 5xx Server Errors by Using a Crawler

If your website is new or you want to know its status right now, you can use SEO technical audit tools like BuhalBu’s Kit. Its spider will crawl each and every of your web pages and will apply a wide collection of audits.

It will tell you about those types of errors, but it can point out to you many other SEO issues and stats that will help you improve your website performance.

Check For 5xx Server Errors in Google Search Console

Your Google Search Console account is also a source of information that tells you about server errors. It’s the easiest way to do it, but there is one catch – it doesn’t report them in real-time.

So if your website is new, there will be no information. Or, if you want to know that your fixes work, you must wait several days. Using an SEO tool like BuhalBu’s Kit, you can audit your web pages in real-time as many times as you like.

The Most Important Types of 5xx Server Errors

500 Internal Server Error

“The server has encountered a situation it does not know how to handle.”

Source: Mozilla.org

Those errors can be seen on a site level when they prevent the users from opening any existing page. Also, they can exist on a page level when they prevent the user from opening specific pages only.

They often result from a software bug or server failure for other reasons.

If you’ve recently updated your website and now it’s not accessible, then the fastest way to recover it and give yourself more time is by restoring it from a backup. That way, it will be active again while you’re debugging or contacting your developer.

Read More: 500 Internal Server Errors: What They Are & How to Fix Them

501 Not Implemented

“The request method is not supported by the server and cannot be handled. The only methods that servers are required to support (and therefore that must not return this code) are GET and HEAD.”

Source: Mozilla.org

As you may know, browsers communicate with your server in different ways. Sometimes they just want to show a web page, so they make a “GET Request.” Sometimes they want to send the server user data, so they make a “POST request.”

The words “GET” and “POST” represent the “method” that the browser is using to communicate with the server.

So if your website doesn’t accept POST requests, it should return a 501 Not Implemented server response if someone makes POST requests.

This is a rare error that can result from strange requests to your website. They can’t be generated in the usual way of browsing. So in most cases, you can safely ignore it if you have spotted it in the logs.

502 Bad Gateway

“This error response means that the server, while working as a gateway to get a response needed to handle the request, got an invalid response.”

Source: Mozilla.org

So your website is located on a server. But the browsers all over the world can’t connect it directly. Their request is “routed,” and the “route” includes many other servers that pass it between different servers.

Moreover, there may be another server right in front of yours in some cases. The so-called “proxy” or “reverse proxy.”

When the proxy redirects a request to your server and doesn’t receive a proper response quickly, the result is 502 Bad Gateway.

So it is very similar to the Internal Server Error (500), but we have possible network issues also involved. If you often receive 502, maybe your server and/or proxy aren’t correctly configured.

Learn more: How to Fix a 502 Bad Gateway Error on Your WordPress Site

503 Service Unavailable

“The server is not ready to handle the request. Common causes are a server that is down for maintenance or that is overloaded. “

Source: Mozilla.org

The definition of this type of error is pretty straightforward. When you put your site on “Maintenance Mode,” it should return this error and a user-friendly page explaining the situation.

504 Gateway Timeout

“This error response is given when the server is acting as a gateway and cannot get a response in time.”

Source: Mozilla.org

Those are really nasty trouble-makers because they can start occurring in a later stage of your online business.

At first, your website is sleek and fast, but when your database becomes larger and your web traffic is more substantial, that may result in slow data retrieving and processing.

Also, they can be provoked by a network problem between the server and the proxy.

Learn more: 504 Gateway Timeout Error: Here’s how to fix a 504 Gateway Timeout error

505 HTTP Version Not Supported

“The HTTP version used in the request is not supported by the server.”

Source: Mozilla.org

That’s pretty clear. I’ve never encountered that error.

506 Variant Also Negotiates

“The server has an internal configuration error: the chosen variant resource is configured to engage in transparent content negotiation itself, and is therefore not a proper endpoint in the negotiation process.”

Source: Mozilla.org

This is one more rare error, and if you’re not responsible for the server configuration, you will probably never encounter it.

507 Insufficient Storage

“The method could not be performed on the resource because the server is unable to store the representation needed to complete the request.”

Source: Mozilla.org

When browsers make POST or PUT requests, they send data to the server. The latter needs to temporarily store that data while your CMS or other web software processes it. If your server doesn’t have enough persistent storage (or even RAM), or the “tmp folder” is limited in size, the server will return 507 Insufficient Storage.

508 Loop Detected

“The server detected an infinite loop while processing the request.”

Source: Mozilla.org

As you may know, every programming language gives the programmer an option to create a “loop.” The loop is an instruction to the computer to execute the same code multiple times.

So instead of the programmer copying a code block, they put it in a loop and configure how many times it must run. Sometimes that configuration isn’t set correctly, leading to the so-called “infinity loops.”


The Server Errors (5xx) are nasty trouble-makers that demand debugging and analyzing. Sometimes you will need a web developer to fix them, and other times, it will be a matter of patience while waiting for a new theme or plugin update.

They need to be resolved in a speedy fashion because a web page that can’t be loaded will soon be removed from the search index and will stop receiving organic traffic.