The web browser sends a request to the web server every time someone visits a website. The server may send a blank page with an HTTP status code instead of responding to the request. This suggests an error.
Most websites may encounter issues at some point during their existence. One of the most commonly encountered issues is the 503 service unavailable error. When a web server is unable to process a request, it returns the HTTP 503 error.
When left unattended, the 503 service unavailable error, like any other server problem, can have a severe impact on a website. As a result, this tutorial will go into the potential causes of this problem and how to properly resolve it.
Let’s start with a definition of the 503 service unavailable error.
- Error code
503 service unavailable error
- Error type
- Error variations
503 Service Unavailable
Error 503 Service Unavailable
503 Service Temporarily Unavailable
HTTP Error 503
HTTPS Error 503
HTTP Server Error 503
HTTP Error 503. The service is unavailable.
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
- Error causes
Resource usage exhaustion
Server communication problems
Sudden traffic spikes
Distributed Denial of Service (DDoS) attack
Incorrect DNS configuration
Plugin or theme incompatibility
Root Cause of 503 Error
HTTP (Hypertext Transfer Protocol) status codes are used to communicate between web browsers and web servers.
Your browser makes queries to the web server that hosts the content whenever you visit a website. Following that, the web server retrieves the requested resources as well as an HTTP response status code.
The five server response codes are as follows.
- 1xx – informational
- 2xx – success
- 3xx – redirection
- 4xx – client-side error
- 5xx – server-side error
Typically, servers merely return the requested website, and browsers do not display HTTP status codes signaling a successful connection. When an error occurs, however, the servers send an error message along with the problem code.
Among these error codes is the 503 service unavailable error. It’s rather common and indicates that the server is temporarily unable to handle the request.
The following are the most prevalent scenarios in which HTTP error 503 messages appear.
- 503 Service Unavailable
- Error 503 Service Unavailable
- 503 Service Temporarily Unavailable
- HTTP Error 503
- HTTPS Error 503
- HTTP Server Error 503
- HTTP Error 503. The service is unavailable.
- The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
The HTTP error 503 service unavailable, unlike other server-side problems, indicates that your web server is operational but cannot be reached at this time. A large number of queries submitted to the server typically causes this, exhausting available resources.
The 503 service unavailable problem will usually go away as soon as the traffic drops. As a result, visitors will be able to read your content after a short time. If the error persists for an extended period of time, it could indicate a more significant problem with your server.
As a result, the next part will demonstrate seven practical methods for determining the root cause and resolving the 503 service unavailable error.
We’ll walk you through seven techniques to diagnose and fix HTTP 503 issues, from evaluating your resource use to viewing server logs.
Check Server Resource Usage
A server’s resources include RAM, CPU, I/O, entry processes, and website inodes. These indicators might help you determine whether the problem is due to a lack of resources. You can, for example, monitor incoming traffic and detect any odd traffic spikes. You’ll find a variety of metrics linked to your website’s resource utilization there, including.
- The amount of CPU power your site uses.
- The total amount of memory that your website uses to process requests.
- The number of processes running on your hosting account is measured in processes.
- Data transfers between the hard disk and RAM are measured in throughput (I/O).
- Total requests – the sum of all hosting accounts’ HTTP and HTTPS requests.
- The data transferred in a given amount of time.
The above indicators can aid in the resolution of the 503 service unavailable problem. Take, for example, the following metric. When your website’s memory limit is exceeded, it slows down overall performance, resulting in HTTP error 503. Upgrade your hosting package to enhance these three server components as a general rule.
Although the CPU can handle multiple requests at once, a persistent load might tire the CPU and cause your site to slow down. As a result, if you have a high volume of queries, you should consider upgrading your CPU capacity.
To stay up and running, a website with a lot of visitors needs additional RAM. The more RAM your website has, the less burden it puts on your CPU, allowing it to function faster and handle more requests.
The faster data goes between your site, users, and the internet, the more bandwidth you have. If your site has a lot of dynamic content, such as graphics and videos, you’ll need more bandwidth to ensure that it loads quickly.
Check for Maintainance Window
Server maintenance is essential for maximizing site performance and reducing security issues.
When a web server or program is being maintained, it is usually set to shut down.
As a result, the HTTP error 503 service unavailable could occur as a result of this unplanned repair. When a new WordPress version is launched, for example, several web hosts frequently give automatic upgrades to their users. During the procedure, the system generates a 503 service unavailable error.
If the 503 error is caused by scheduled maintenance, contact your hosting provider. Users of Hostinger can simply browse to our status page to check real-time system updates.
Alternatively, you can change the settings on your server and turn off automatic updates. You’ll have complete control over server upkeep this way.
Check Running Processes
Exceeding the maximum process limit is another common cause of the 503 service unavailable message. When your web server runs too many processes at once, it can become overloaded and cease responding.
Stopping running processes is required to bring your site back online. Users of VPS hosting can use the kill command line to terminate a process.
Meanwhile, shared hosting customers can access to the Order Usage page in the hosting control panel. Scroll down to the bottom of the page until you see the option to Stop running processes.
The Stop button will terminate all running processes on your website. Keep in mind that this is only a band-aid solution; you’ll need to dig deeper to figure out what’s causing so many processes to run at the same time.
Examine your WordPress themes and plugins first, as they can consume resources and cause conflicts.
If you get an HTTP 503 error after installing a plugin, you’ve located the source of the problem. If you can’t figure out which plugin is causing the issue, you may need to disable all of them and then enable them one by one.
Aside from plugins, 503 problems can also be caused by poorly designed WordPress themes. To fix this, consider switching to a default WordPress theme like Twenty Nineteen or Twenty Twenty.
Some scripts or applications may be utilizing more resources than your current plan allows if you continuously surpassing the maximum process limit. You’ll need to either optimize your website or improve your hosting plan in this situation.
Check Firewall Settings
A web application firewall (WAF) prevents any potentially harmful traffic from entering your site. To put it another way, the firewall protects your website against dangerous activities such as brute force and DDoS attacks, as well as cross-site scripting and SQL injections.
Incorrect firewall settings, on the other hand, can identify false positives and block connections from a certain client. For example, your firewall may misinterpret a safe request from a content delivery network (CDN) as malicious, causing critical traffic to be blocked and 503 errors to be generated.
Reset your firewall configuration to fix the problem. VPS users can reset the firewall by going to the admin panel, going to the VPS Management section, and clicking Reset Firewall.
However, depending on your hosting provider, the stages will differ. It’s better to get in touch with the support team and ask for help.
Check Server Logs
Check your error log if the 503 error still persists.
Server-side logs keep track of everything that happens on your website, from visitors’ requests for web pages to system failures. You can more quickly discover and correct mistakes by using information from the logs.
The website error log is usually accessible through the admin panel of your hosting provider. Users of Hostinger should go to Advanced -> PHP Configuration in cPanel.
To save your changes, scroll down. Whenever a problem occurs, go to the public html directory, open the wp-content folder, and look at the error log file.
You may also enable error reporting in the wp-config.php file by adding the WP DEBUG PHP constant.
To begin, navigate to the wp-config.php file in your website’s root directory.
- Click on the public_html folder and choose wp-config.php.
- Add the following code inside the file:
define( 'WP_DEBUG', true ); define( 'WP_DEBUG_LOG', true ); define( 'WP_DEBUG_DISPLAY', false );
- Click the Save and Close button.
You may also access the server error log on your web server software by going to the following file:
/var/log/nginx/error.log/ Nginx server
/var/log/apache2/error.log/ Apache server
Connectivity difficulties between the server network hosting your application can cause the 503 service unavailable error.
Rebooting your server is one of the quickest solutions to fix the 503 service momentarily unavailable problem if you have root access to your website. If your website is housed on many servers, make sure to reload each one to bring it back to life.
If the 503 service unavailable error persists, the issue could be caused by temporary problems with your computer devices or home connection. This can happen if your devices are unable to process requests due to network misconfiguration.
In this situation, a simple restart would suffice: turn off all networking equipment, wait a second, and then turn it back on. Reconnect your computer to the network and reload your webpage once it’s finished.
A DNS-related issue, such as unresolved IP addresses, unresponsive DNS servers, or a misconfigured DNS cache, is another probable cause of the 503 error.
Flushing your DNS is one efficient technique to resolve this problem. Your operating system determines how to cleanse DNS cache. We’ll teach you how to do this on Windows, macOS, and Google Chrome in the sections below.
sudo killall -HUP mDNSResponder
You’ll be directed to the internal settings page. Select the Clear host cache option from there.
Another option is to temporarily change your DNS servers. Your ISP assigns your DNS servers by default, but you can change them to third-party servers like Google Public DNS.
When a server is unable to handle a request, the 503 error is displayed. This error usually happens during server maintenance. However, resource disruptions might also result in 503 errors.
Although the problem normally goes away on its own, leaving it ignored might have a severe influence on your site’s performance and user experience.
Overall, we hope these troubleshooting procedures assist you in resolving the HTTP error 503 and restoring your website. If you have any more questions, please share them in the comments area below.