How Do 5xx Server Error Affects Your SEO Health?

5xx server error

A good SEO strategy does not focus on outbound connections; it prioritizes inbound efforts. This is why you have to be on the lookout for a 5xx server error that affects your site’s health and search rankings.

A successful search engine optimization (SEO) strategy is vital to the growth of your business. Think of SEO as your introduction to the online community. It is how you enter the radar of your intended audience.

Now imagine, the first thing that your customer encounters with your brand is a server error. Quite unpleasant, huh? This would naturally be a negative user experience impacting both the way Google views your website and the way your customers perceive your brand.

Therefore, you should be on a lookout for any 5xx server error on your site. In this article, we cover what is 5xx server error as well as the most common issues causing them.

What Are the 5xx Errors that Affect Site Ranking and Indexing?

5xx errors specify server problems that prevent a page from loading. These errors may lead to a negative user experience which, in turn, lowers search engine rankings or causes a Google deindexation.

The 5xx group of HTTP status codes includes errors wherein the server is unable to meet a valid HTTP request from a client. In short, there was no issue from the client’s side but the server still couldn’t process the request. These errors appear during the last step of the request-response cycle when your client communicates with a server to access a web page.

To understand the 5xx error types, let’s see the different ways a 5xx server error prevents clients from accessing your content and connecting with your brand:

500 – Internal Server Error

This error is a generic error message that lets clients know that the server encountered an unexpected condition. It occurs when the application is incorrectly configured.

501 – Not Implemented

In this case, either the server does not support the HTTP request or the server is out of date. This error rarely occurs and generally requires a web server update.

502 – Bad Gateway

A bad gateway error occurs when the server while acting as a gateway or proxy, is improperly configured and receives an invalid response from the upstream server. It can also be the result of poor IP communication when the server is overloaded or a firewall is malfunctioning. Clearing the cache should help solve the issue.

503 – Service Unavailable

A 503 error occurs when the server is temporarily overloaded or under maintenance. It indicates that the server will be back up shortly.

504 – Gateway Timeout

504 server error

Image source: https://www.oncrawl.com

A gateway timeout is the result of slow communication between the server acting as the gateway and the upstream server. It is the lack of a timely response from upstream computers.

505 – HTTP Version Not Supported

As the name implies, the server does not support the HTTP protocol used by the client. It cannot accommodate the request based on the HTTP version the client is using.

506 – Variant Also Negotiates

This error commonly occurs when the internal server is not properly configured as an endpoint. Rather, the server was only configured to engage in transparent content negotiation.

507 – Insufficient Storage

The 507 error occurs when the server runs out of memory needed to complete the HTTP request. This is often addressed by freeing up the server’s hard disk space, expanding the memory, or simply restarting the application.

508 – Loop Detected

In this situation, the server terminates an HTTP request because it encounters an infinite loop.

509 – Bandwidth Limit Exceeded

As the name implies, a 509 error occurs when the HTTP request exceeds the system administrator’s bandwidth limit – the amount of data that can be transferred from your site to the user’s computer. It can be addressed either by acquiring more bandwidth or waiting for the next bandwidth cycle to reset the limit.

510 – Not Extended

Some HTTP requests require further extensions before the server can process them. A 510 error occurs, therefore, when the extension is not supported by the server. It requires a server update to be fixed.

511 – Network Authentication Required

This error pops up when the client needs network authentication before the server grants them network access. An example is when a client must show some authentication or accept Terms of Service before gaining full access via a Wi-Fi hotspot.

If the server experiences a problem while a searcher tries to access a web page, the request-response cycle leads to any one of these errors. As they all prevent potential site visitors from interacting with your website you lose leads that could boost your SEO ranking. 

In What Ways Can 5xx Server Errors Negatively Affect Your Search Rankings?

Saying this from own experience, you have to minimize the 5xx errors that appear on your website. Not only it affects your site’s rankings, but it also leaves your customers unsatisfied.

In some cases, 5xx errors are unavoidable. For example, server downtime is only natural when you are updating your website or implementing fixes. Regardless of the occasional need for it, downtime shouldn’t run for too long. It may result in lower search engine visibility and, in turn, lower rankings.

Let’s take a look at the different ways server errors can take a toll on your search rankings.

Intermittent 500 Internal Server Errors Lead to a Drop-in Crawl Stats

A 500 Internal Server Error occurs due to server instability. This means a specific URL would alternate between returning a 200 Success response and a 500 Internal Server Error response. 

Success responses may occur more frequently than the internal server error but the reoccurrence of the error could still cause crawl stats to go down. This case study shows that a 500 error can actually cause a significant decrease in pages crawled per day, resulting in a negative rankings shift.

Google crawlers described the intermittent 500 errors, which lead to the search engine giant dropping 2,122 keywords from their Top 10 search rankings according to the Google Search Console Crawl Errors report. Additionally, 2,959 keywords that were ranking between 11 and 20 dropped lower than 20.

Throughout the case study, it was evident that organic traffic decreased due to server errors. It actually dropped by 25 percent, causing a direct impact on the overall search rankings. After the server instability was addressed properly and the errors subsided, traffic and rankings went back up.

Prolonged Downtime Causes Drop in Rankings

Another example of how server errors affect SEO strategy is how a prolonged downtime period can cause a major drop in keyword ranking. The previously mentioned case study also observed that web pages that were consistently returning 500 error responses for approximately 18 hours experienced a drastic drop in the rankings. 

For tracked keywords, the domain ranking dropped anywhere between 5 and, more significantly, 100 positions. But if there was a similar page that Google chose to rank, the drop wasn’t as dramatic. It ranged anywhere between 5 and 20 positions depending on how relevant Google considered the domain.

The case study included 239 tracked queries with 500 error responses during an 18-hour downtime. The actual downtime lasted for less than a day but it affected an entire week’s page ranking report. The queries had an average ranking drop of 10 positions.

On another note, not all rankings dropped drastically. Some queries with similar pages from the same domain dropped only a few positions on Google search rankings. Alternatively, tracked keywords dropped considerably when the domain lacked subcategory pages featuring them.

What Are the Implications of these Errors on Your Website?

The truth is nobody outside of Google knows exactly how often Google crawls and re-indexes websites. It depends on how quickly the search engine algorithm can notice and process changes on a site or a page. However, Google does crawl and index websites and pages often enough that a simple 500 Internal Server Error or any other 5xx error can immediately take a toll on search engine rankings.

The search engine giant uses a web crawling software called Googlebot to gather information about websites. The software has two crawlers — a desktop crawler which checks the accessibility and connectivity of web pages on a desktop and a mobile crawler, which analyzes a site’s mobile-friendliness.

Both crawlers report back to Google especially when server downtimes occur frequently. If Google’s algorithm decides that the 5xx errors have been going on for too long and too often, the search engine is bound to replace those web pages with other seemingly more relevant pages.

So now that you know how 5xx server errors can impact your site’s SEO, we will give you possible solutions to fix these errors.

How Do You Find a Remedy for 5xx Server Error?

Incompatible server updates, corrupted files, and script errors are all common culprits of 5xx errors. If your website or page encounters one of these errors, you can try reloading the page to check if it is only a momentary issue. You may also check or request a copy of the error log if you have a hosted website to pinpoint the cause. If either of these doesn’t work, you may look into these common causes of 5xx errors.

Installation of New Plugins

This is a common cause of 5xx server error. Some plugins might fail while interacting with other plugins or themes on your site. Consider rolling back on any newly installed plugins or themes until the 5xx error disappears. In this way, you will find the cause of the error by pinpointing the responsible plugin or theme, if that is the case.

Failure of Software Upgrade

If the error appeared after the software was just upgraded, then it might have been the culprit. Check for missing or corrupted files during the upgrade and try reinstalling the upgrade. The issue might be either with the installation process or with the existing plug-ins and themes.

Incompatibility of Software Upgrade

If you have new or upgraded software, it may not be compatible with your existing themes and plugins. In this case, you might have to deactivate existing apps until you determine which one is causing the error.

Incorrect Permissions

The host server may require different permissions. Incorrect permissions on a folder or a file containing one of the scripts might cause issues. To resolve it you should check what permissions are needed and make sure that they are correctly set on the server.

Moreover, server-side scripts might be causing a 5xx server error. Try debugging your server scripts to address the 5xx errors. These are the different problems that scripts may encounter:

  • Server Permission – A server cannot run a script if the given permission is incorrect.
  • PHP Timeout A server that connects to external services and times out multiple times can lead to an error.
  • Server Timeout – A server might time out due to multiple reboots and lost connections.
  • Structure in .htaccess Files – The .htaccess file might be preventing a page from loading. In this case, you might have to rename or temporarily take down the file before the page can reload properly.
  • CGI and Perl Script Errors – Make sure that all .cgi and .pl extensions are supported by the server.

Wrap Up

From generic server errors to gateway timeouts, 5xx errors inevitably affect the rankings that an SEO strategy steadily builds.

If you are targeting higher search rankings, it isn’t enough for you to focus on the major traffic channels like organic search, social media, paid media, and email marketing. You have to check, maintain, and update the website or landing pages that these digital marketing efforts point to. This means resolving 5xx server errors before they cause your target market to turn away and Google to lower your ranking.

Address 5xx errors before they take a toll on your extensive SEO efforts.


Paul Staten is the co-founder and CEO of SEO Werkz, a Utah SEO Company. He is famous for delivering his twins at home and trying out for American Idol and being immediately rejected. In 6 years of Operation, Paul and his team have helped hundreds of small businesses earn a positive ROI in the digital space. His leadership has earned the company a place in the Inc. 500 as one of the fastest-growing privately held companies in the US. You may connect with him on LinkedIn.