The HTTP code 503 is one of the most common error messages and we will tell you what it is and what happens when you see this error. In some cases, it is enough to refresh the page, but in other cases, the message does not disappear even after refreshing the browser several times. And it doesn’t matter whether you are browsing on your desktop, tablet, or cell phone because with the HTTP status code 503 – Service unavailable the server only informs the user that the page he wants to access is temporarily unavailable. What is the 503 error, why does it occur and what options do the user and the server administrator have to solve it? Read on.
What does the HTTP error code 503 – Service unavailable mean?
Error code 503 is one of several status codes with which a server can respond to HTTP requests from clients such as a browser. With them, it can inform the browser that the request has been processed successfully or it can indicate whether further steps are still required on the client’s side. Error 503 belongs to the class of HTTP status codes that reports the server’s inability to process a request and the message that is sent is “service unavailable”, which signals to the client that the server is momentarily offline. In the Retry-After field of the HTTP response header, you can indicate a later time when it is more likely to be possible to process the request.
When does the error message 503 (service unavailable) appear?
HTTP error 503 occurs whenever a server is unable to deliver the requested resource at the time the client requests it. Roughly speaking, this can be due to three reasons:
The server is undergoing maintenance work to install updates, copy databases or create backups and during the procedure, it is not connected to the Internet.
The server is overloaded because it receives more requests than it can process and therefore responds with the error message. This can be due to either an unexpected traffic spike or a continuous growth of the project without an increase in the required resources. Other possible causes include malware or spam attacks or faulty programming of the web application or content manager.
In rare cases, it is a faulty DNS server configuration on the client-side (computer or router) that leads to the 503 error message. And if the selected DNS server itself temporarily has problems, the HTTP request also gets the error message in response.
There are content managers such as WordPress that have plugins in their catalog to create their own 503 error pages, such as WP Maintenance:
How to fix HTTP error code 503?
The 503 error message is as annoying for visitors as it is for project administrators, but not being able to open a page is especially problematic when the service offered on the page is needed urgently, such as when you want to close a bank transaction or send an email. When using web applications or cloud services such as online games, office applications, storage platforms, or project tools in both private and professional life, you are not prepared to wait forever for the page to be available again.
In addition to the user, the web project manager is also interested in the resolution of the server availability problem that is revealed by the 503 error. Lack of accessibility leads to user dissatisfaction and loss of traffic, and, if the problem occurs frequently, it could lead to a worsening of the search engine ranking.
Error 503: solutions for client application users
If, when trying to enter a web project with the browser, you get the status code 503 in response, you will hardly be able to find out the reason for such a message with the little information available to you, except for the aforementioned case of pages under maintenance. These are planned by the administrator and are usually reflected in custom 503 error pages that often also include information about the duration of the service interruption. If nothing indicates that it is maintenance work, you can try to solve this problem with the tricks we reveal below:
Reload the page
It is possible that the server may not be able to respond correctly to the HTTP request on time. In this case, simply refresh the page by clicking the “Refresh” button next to the browser address bar, typing [F5], or using the shortcut [CTRL] + [R].
Restart your computer and router or change your DNS server
We mentioned earlier that the cause of a 503 error may well lie in a problem with the name server. If this is the case, it is usually specified with the message “Service Unavailable – DNS Failure”, which, on the one hand, maybe due to a wrong DNS configuration of the system or router and, on the other hand, maybe the result of a technical problem with the selected name server. While the first possibility can be solved by restarting the computer, the solution to the second is to select a different server. Find out in our guide what steps you need to take to do this.
Visit the website again later
If you have followed these steps and still have no success, it is advisable to close the page and try visiting it later. As this unavailability is often linked to a sudden increase in traffic, procrastinating helps to reduce the load on the webserver and enables the normal processing of all HTTP requests. The same applies to cases where the 503 error occurs due to maintenance work, but the administrator does not properly inform the user with a specific error page.
Contact the website administrator or the help desk
When a website is unavailable for an extended period, you may want to contact the administrator in charge or the helpdesk whenever possible. This will provide you with information about the triggers of the 503 error and the current status of the issue.
How to fix the 503 error: options for server administrators?
Web server administrators are the first to want to solve this problem as quickly as possible, or even to ensure that it never occurs at all, mainly for the reasons mentioned above, i.e. disappointed visitors, loss of traffic, and possible penalization by search engines. Of course, this is not always possible, as in the case of maintenance work, when temporary disconnection of the server is unavoidable.
However, by using customized error pages, it is possible to inform visitors of the unavailability without making the interruption too annoying. It is advisable to define the expected duration of the service interruption, provided that the duration of the maintenance work can be estimated. In the following paragraphs, we have compiled some tips and tricks around the HTTP 503 error code.
Keep an eye on the hosting resources you require
Traffic is, in all probability, the key aspect of the 503 error problem because, on the one hand, one of the main objectives of any manager is to attract as many visitors to the site as possible but, on the other hand, its increase can easily lead to the overloading of the webserver and the appearance of the dreaded 503 error. Consequently, it is key to keep control over the traffic figures and to expand the hosting resources when necessary to ensure a stable service in the long term. If, for example, you are managing a project that is dependent on seasonal events such as Christmas shopping e-shops, it is advisable to opt for a hosting solution that allows for temporary expansion of server capacity.
Regularly update the software you use
When the 503 error is triggered by malware or spam, it is advisable to contact the operator immediately and work together to find a solution to the problem. To prevent this situation from arising, take care of the security of your project from the very beginning. The provider’s terms and conditions play an important role here because, depending on the package contracted, the responsibility for protection may fall to you to a greater or lesser extent. For example, always opt for current software and install available updates when recommended. Outdated applications with known weaknesses quickly mutate into a target for attacks.
Detect and resolve programming errors
Another cause of a server-side 503 error can be found in poor programming of the project or content management software. WordPress, for example, easily falls into this error, resulting in a long loading time, but it can also be due to a high number of database accesses or poorly programmed plugins that, although they add functions to the CMS, also slow down its performance. The same applies if too many extensions are installed. The key is, therefore, to filter out the most problematic plugins to deactivate them if necessary.