Oct 9, 2023 12 min read

How to Fix 503 Service Unavailable Error: 7 Steps That Work

Fix 503 Service Unavailable Error with our step-by-step tutorial. A web browser sends a request to the server for each website access.

Fix 503 Service Unavailable Error: 7 Steps That Work
Table of Contents


Before we begin talking about how to fix 503 Service Unavailable Error, let's briefly understand – What is Service Unavailable Error?

A request is made to the web server by the web browser each time a user accesses a website. Occasionally, instead of responding to the request, the server provides a blank page with an HTTP status code. This suggests an error.

Do not worry, most websites have errors at some point. One of the issues that people run into the most is the 503 service unavailable error. When they are unable to process a request, web servers always return the HTTP 503 error.

When left unfixed, the 503 service unavailable error, like any server faults, can have a harmful influence on a website. As a result, this article will explore the potential reasons for this problem as well as viable solutions.

Let us begin by discussing what the 503 service unavailable error is in more detail.

Error code - 503 service unavailable error

Error type - Server-side error

Error variations :

  1. 503 Service Unavailable
  2. HTTP Error 503. The service is unavailable.
  3. Error 503 Service Unavailable
  4. 503 Service Temporarily Unavailable
  5. HTTPS Error 503
  6. HTTP Error 503
  7. HTTP Server Error 503
  8. The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

Error causes:

  1. Plugin or theme incompatibility
  2. Faulty DNS configuration
  3. Sudden traffic spikes
  4. Server communication problems
  5. Resource usage exhaustion
  6. Distributed Denial of Service (DDoS) attack

In this tutorial, you will fix 503 Service Unavailable Error. We will also address a few FAQs on how to fix 503 Service Unavailable Error.

What Is 503 Service Unavailable Error and What Causes It?

The HTTP (Hypertext Transfer Protocol) status codes are used for interaction between web browsers and web servers.

Your browser makes queries to the web server hosting the content each time you access a website. The requested resources are then retrieved by the web server, along with an HTTP response status code.

The five server response codes are mentioned below:

  • 1xx – informational
  • 2xx – success
  • 3xx – redirection
  • 4xx – client-side error
  • 5xx – server-side error

Browsers typically do not show HTTP status codes, which indicate that a connection was successful, and servers typically just return the requested page. Yet, the servers always send a message along with the error code when a problem occurs.

These error codes include the 503 service unavailable error. It frequently occurs on the server side and demonstrates that the server momentarily is unable to handle the request.

Here are some of the most common ways the HTTP error 503 messages can appear in:

  • 503 Service Unavailable
  • HTTP Error 503. The service is unavailable.
  • Error 503 Service Unavailable
  • 503 Service Temporarily Unavailable
  • HTTPS Error 503
  • HTTP Error 503
  • HTTP Server Error 503
  • The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

Unlike other server-side errors, the HTTP error 503 service unavailable signifies that your web server is operational but is not reachable at the moment. It is usually triggered by a large number of requests being submitted to the server, which exhausts available resources.

Most of the time, the 503 service unavailable error will go away as soon as the traffic decreases. Thus, after a short wait, allow visitors to view your content. The error might, however, be a sign of a more significant issue with your server if it continues for a long time.

Therefore, the following section will outline seven effective methods for identifying the source of the 503 service unavailable error and fixing it.

7 Steps to Find Root Cause and Fix the 503 Error:

We will go over seven strategies to identify and resolve HTTP 503 errors, from monitoring your resource usage to viewing server logs.

1. Check Resource Usage

A server's resources include Memory, CPU, I/O, entry processes, and website inodes. You can determine if the problem is due to a lack of resources by looking at these metrics. You may, for instance, keep an eye on incoming traffic and notice any unusual spikes in it.

Excellent resource usage monitoring features are available in Hostinger's hPanel. The dashboard can be accessed by users, who can then go to Order -> Order Usage.

From there, you may see numerous resource usage stats for your website, such as:

  • CPU – the amount of CPU power used by your site.
  • Memory limit – total memory used to process requests on your website.
  • Processes – the amount of processes that are active on your hosting account.
  • Throughput (I/O) – the rate at which data is transferred between RAM and the hard disk.
  • Total requests – the total number of requests for HTTP and HTTPS across all hosting accounts.
  • Bandwidth – data transferred in a certain time frame.

These metrics will assist you in resolving the 503 service unavailable error. Take a look at the following metric:

The red line in the graph above indicates the upper limit of your current plan, and the blue line displays how much RAM your website is now using. When your website uses more RAM than allowed, it will perform worse overall and return the HTTP error 503.

As a general guideline, you should upgrade your hosting package to include more of these three server components:

  • CPU. Even though the CPU has the capacity to handle several requests at once, a continuous load might wear down the CPU and reduce the speed of your site. Hence, it is better to upgrade your CPU capacity if you receive a lot of requests.
  • RAM. More RAM is required to keep a website that receives a lot of traffic up and running. Your website will put less strain on your CPU if it has more memory, which will speed up server operation and enable it to handle more requests.
  • Bandwidth. Data transfers between your website, users, and the internet happen more quickly the more bandwidth you have. If your site has a lot of dynamic content, such as videos and images, you will need a higher bandwidth allowance to ensure that it loads quickly.

2. Check for Ongoing Maintenance

To maximize site speed and reduce security threats, regular server maintenance is essential.

Pro Tip: To acquire information on how to improve the performance of your site, use tools like GTMetrix.

A web server or application is typically configured to shut down whenever it is undergoing maintenance.

As a result, during this unscheduled maintenance, the HTTP error 503 service unavailable may appear. When a new version of WordPress is published, for instance, certain web providers usually offer their users automatic upgrades. Throughout the procedure, the system automatically generates the 503 service unavailable error.

To determine whether scheduled maintenance is the cause of 503 error, get in touch with your hosting provider.

As an alternative, you can alter the server configuration settings and turn off automatic updates. You will have complete control over your server maintenance this way.

The procedures to stop automatic updates on Hostinger's hPanel are as follows:

1) Go to Website -> Auto Installer on your hPanel dashboard. Next, select WordPress.

2) Next, provide all the required data, including your domain name and the administrator login details.

3) Three options for automatic updates are available at the bottom of the page. Choose Turn off automatic application updates to proceed.

4) After selecting Install, wait for the procedure to finish.

3. Stop Running Processes

Overriding the maximum process limit is another frequent issue that results in the 503 service unavailable error. Your web server may overload and stop responding if it processes too many requests at once.

You will need to stop running processes if you want to bring your site back online. Users of VPS hosting can kill a process by using the kill command line.

Users of shared hosting can access the Order Usage page by going to the hosting control panel. The Stop running processes option can then be found by scrolling to the bottom of the page.

All running processes on your website will be terminated when you click the Stop button. Remember that this is only a temporary solution; further research is required to determine what is causing so many processes to run at once.

It is a good idea to start by looking over your WordPress plugins and themes because they can conflict with one another and use resources.

When you install a particular plugin and then get the HTTP 503 error, you have identified the problem. You might need to disable all plugins and then re-enable them one at a time if you can not figure out which one is the issue.

The 503 errors can also be brought on by improperly designed WordPress themes in addition to plugins. Try switching to a default WordPress theme, like Twenty Nineteen or Twenty Twenty, to see if it helps.

If you continue to surpass the maximum process limit, some scripts, or apps may be consuming more resources than your current plan allows. You will need to upgrade your hosting plan or optimize your website speed in this situation.

4. Reset Firewall

A web application firewall (WAF) prevents any malicious traffic from entering your website. In other words, the firewall guards your website from harmful activities like cross-site scripting and SQL injections, as well as brute force and DDoS attacks.

Yet, a misconfigured firewall can identify false positives and prevent connections from a particular client. For instance, your firewall may mistake a secure request from a content delivery network (CDN) for malicious activity, blocking important traffic and resulting in 503 errors.

Reset your firewall setup to fix this issue. Users of Hostinger VPS can reset the firewall by navigating to the VPS Management section and clicking Reset Firewall.

However, the procedures will differ depending on your hosting service. Contacting the support team for assistance is recommended.

5. Check Server Logs and Fix the Code

If the 503 error continues, try checking your error log.

Server-side logs keep track of everything that happens on your website, from user requests for specific web pages to system errors. You can identify and fix errors more efficiently if you use information from the logs.

The error log for your website is often accessible from the admin dashboard of your hosting service. Users of Hostinger should log in to hPanel and select Advanced -> PHP Configuration.

Next, select the PHP Options tab and make sure the logErrors checkbox is selected.

To save the changes, scroll down. When an error occurs, open the wp_content folder in the public_html directory and check the error log file.

Adding the WP_DEBUG PHP constant to the wp-config.php file will also enable error logging.

To begin, navigate to the root directory of your website and find the wp-config.php file. Users of Hostinger can log in to hPanel and select Files -> File Manager.

1) Choose wp-config.php by clicking the public_html folder.

2) Within the file, add the following code:

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );

3) Click the Save and close button when you are finished.

Also, you can access the following file in your web server software to check the server error log:

  • Nginx server: /var/log/nginx/error.log/
  • Apache server: /var/log/apache2/error.log/

6. Restart Your Server and Networking Equipment

The server chain that is hosting your application may experience connectivity issues, which can result in the 503 service unavailable error.

So, restarting your server is one of the simplest ways to resolve the 503 service temporarily unavailable error if you have root access to your website. In order to restore everything to normal, make sure to refresh each server if your site is hosted on multiple servers.

Users of Hostinger can access the Server Management page and select the Reboot option to do this.

If the 503 service unavailable error continues to occur, there may be momentary problems with your computer device and home connection. This may occur as a result of incorrect network configuration, which prevents your devices from responding to requests.

In this situation, a simple restart would suffice: turn off all networking equipment, wait a second, and then turn it back on. When finished, reload your website and then connect your machine to the network.

7. Check Your DNS

A DNS-related issue, such as unresolved IP addresses, unresponsive DNS servers, or a corrupted DNS cache, is another potential cause of the 503 error.

DNS flushing is one practical solution to this problem. Your operating system will determine how to flush the DNS cache. The steps to get this done on Windows, macOS, and Google Chrome are provided below.

Microsoft Windows

Open the command prompt on Windows and type the following command:

ipconfig /flushdns

The command deletes all DNS files and restarts the DNS resolver cache. Once the DNS has been successfully flushed, a confirmation message will show up.


Mac users can press F4 to launch Terminal and enter the following command:

sudo killall -HUP mDNSResponder
Important! Commands differ depending on the version of macOS.

Google Chrome

Users of Google Chrome can clear their DNS cache in the web browser.

Launch the software and type the following URL into the address bar:


You will be directed to the internal settings page. Choose the Clear host cache option from there.

Another approach to try is switching your DNS servers momentarily. Your ISP by default assigns your DNS servers, but you can always switch to third-party servers, like Google Public DNS.

FAQs to Fix 503 Service Unavailable Error

How can I fix the "503 Service Unavailable" error? 

Some common solutions include refreshing the page, checking server status, clearing cache, restarting services, and verifying server configuration.

Why am I seeing a "503 Service Unavailable" error on my website? 

A "503 Service Unavailable" error can occur due to high traffic, server maintenance, misconfiguration, resource limitations, or issues with backend services.

How can high traffic cause a "503 Service Unavailable" error? 

High traffic can overwhelm server resources, leading to a "503 Service Unavailable" error. It can be mitigated by optimizing server setup or using load balancing techniques.

What steps can I take if my server is undergoing maintenance? 

During maintenance, it's best to display a custom "503 Service Unavailable" page, inform users, set a Retry-After header, and resume service once maintenance is completed.

Why should I clear the cache to resolve a "503 Service Unavailable" error? 

Cached files may become corrupted or incompatible due to server changes, causing a "503 Service Unavailable" error. Clearing cache can resolve the issue.

What server configuration issues can trigger a "503 Service Unavailable" error? 

Misconfigurations such as incorrect proxy settings, improper SSL/TLS certificates, or limited server resources can lead to a "503 Service Unavailable" error.

Can a plugin or extension cause a "503 Service Unavailable" error on my website? 

Yes, incompatible or misconfigured plugins or extensions can conflict with server resources, triggering a "503 Service Unavailable" error. Disabling them can help resolve it.


An HTTP status code of 503 indicates a request cannot be processed by the server. This issue typically happens when a server needs maintenance. However, resource outages might also be the cause of 503 errors.

Although the problem normally resolves itself, if left untreated, it can have a negative impact on your site's performance and user experience. In light of this, we have compiled seven effective methods to fix  problem and return your site to normal.

Let’s do a quick recap:

  1. Check resource usage – Check your resource metrics to see if the problem is caused by excessive usage. Upgrade your hosting plan if necessary.
  2. Check for ongoing maintenance – If you want to find out if scheduled maintenance is taking place, get in touch with your hosting service provider.
  3. Stop running processes – Kill any running processes that are taxing your server's resources.
  4. Reset firewall – Reset a firewall that was incorrectly configured using the hosting admin panel.
  5. Check server logs and fix the code – Examine the error logs for your website and fix any suspicious codes.
  6. Restart your server and networking equipment – Restarting your server and networking devices will fix any potential configuration issues.
  7. Check your DNS – Clear your DNS cache and temporarily switch to public DNS on your server.

We truly hope that following these troubleshooting methods will enable you to fix HTTP error 503 and restore your website. If you have any suggestions or queries, kindly leave them in the comments section.

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