HTTP error 503 indicates that a website isn’t available for access at the moment. There are multiple reasons why this could happen, such as periodical maintenance by website administrator or server overload. This error message could appear in any platform or operating system. In order to verify whether the problem isn’t device related; you can try to access the website using a different device.
What is 503?
The webpages are physically stored in web servers. Whenever a browser requests a webpage, the web server on which the webpage is physically stored returns a three digit code. This is called status code as this code indicates the status of the HTTP communication. There are many HTTP status codes that a web server returns depending on the situation. 503 is one such a HTTP status code returned by a web server if the requested page is unavailable due to service problem.
Generally 503 service unavailable error will show the below message on browser, but it can be different as well:
Additionally, a 503 Service Unavailable error was encountered while trying to use an ErrorDocument to handle the request.
It will be shown on the browser along with the server details like below:
Remember website owners should pay money to hosting company to keep their content on web servers. The web hosting companies offer web servers with a limited resources like CPU and RAM based on the purchasing plan. So there are many possibilities that the hosting company may cut the service which results in 503 service unavailable error.
1. Check the Site is Up
The first thing you need to verify is whether it’s a server-side problem. Use site up or down checker to find out about the status of the website you are trying to access. You simply need to type in the target URL to know whether the website is accessible.
If it is confirmed that the website is down, your options are very limited. You may need to wait until the website is accessible again. If the website is accessible through other devices and online tools, then the problem is likely with your computer. Below are things you should do.
2. Repair Your Registry
You may need to repair Windows registry to gain access to the website. Do this carefully, because incorrect editing may cause irreversible damage. In fact, it is possible that your PC fails to boot, due to a missing comma in a registry entry. If you are not sure about editing registry, you may try trusted registry cleaners, such as Reimage.
A reliable registry cleaner will look for missing file references, which may potentially cause service unavailable error. These registry cleaner tools can also solve other registry problems like broken links and invalid registry entries. Make sure that the tool creates registry backup before starting the cleaning process, so any unwanted change can be undone. Often, you notice improvement in stability, reliability and performance after performing registry cleanup.
3. Scan for Malware
There’s a good chance that 503 service unavailable error is caused by malware infection. These nasty malware codes can cause many problems, including blocking access to your favorite websites. Scan your computer thoroughly with antivirus software.
Sometimes you may need to install a new malware cleaner tool if your existing antivirus software could not help.
4. Clear Temporary Files
If you browse the web often, your computer will accumulate a lot of junk files over time. Your Windows OS will perform sluggishly if the junk isn’t cleaned out regularly. These files could also increase the possibility of file conflicts. In some cases, you can prevent HTTP 503 error by performing temporary files cleanup. Disk Cleanup is a useful built-in Windows tool that can quickly remove temporary files. However, you should know that Disk Cleanup may not remove junk files created by some programs, like Microsoft Office. But, most of the time, Disk Cleanup should be enough to make your file system cleaner. Follow these steps:
- Type in cleanmgr in the search box and click on the result.
- Let Disk Cleanup to analyze your partition and often, temporary files represent a major part of your junk files.
- Remove the junk files and repeat the process for other partitions.
On Mac, you can do disk cleanup using third party apps like Dr.Cleaner. You can scan for junk files and delete them.
5. Update Device Drivers
Outdated or corrupted device drivers could contribute in causing HTTP 503 error. For an unknown reason, it is possible that the driver fails to work one day. An easy way to solve this is to update the driver. If you have corrupted device driver, reinstalling could also solve the problem. In order to avoid incompatibility, you should download the driver directly from the official website of the device manufacturer. If you get a major driver update, it is possible that you obtain more features and much better reliability. The performance and speed of your computer could improve as well. When troubleshooting HTTP 503 error, you can update network related device drivers first. Learn how to change network settings in Windows 10.
6. Roll Back to Previous Restore Point
It is always a good practice to set a restore point when your computer is working perfectly. Eventually, issues will happen and rolling back to the restore point can help you fix them; including HTTP 503 service unavailable error. It’s easy to do and you can avoid complicated troubleshooting procedures. Follow these steps to restore your PC:
- Type in “System Restore” in the search field
- Click on the “System Restore” on the search result
- If prompted, enter your administrator password and follow the instruction.
- Check whether the problem has been resolved
7. Reinstall Network Related Programs
Reinstalling network related programs could solve 503 service unavailable error. Often, the developer has released the latest version of the program, offering better stability and more features. One of the simple examples for network related program is VPN applications.
Follow these steps to uninstall programs in Windows:
- Go to the official website of the software developer and download the latest version of the program
- Go to Control Panel> Programs> Programs and Features
- Locate programs that you want to reinstall. Choose one and click on the Uninstall button. Similarly uninstall the remaining programs
- Restart your computer and check the site can be accessed
- If you can access the sites then reinstall these programs by using the recently downloaded software files
- If the site could not be accessed then the problem could lie in different area.
On Mac, you can just drag and drop the application file to uninstall the program.
8. Check Windows System Files
Windows OS comes with a tool that checks and restores corrupted Windows system files. Follow these steps:
- Type in “sfc/scannow” in the search box
- Click on the System File Checker
- Use the tool to scan the system for damaged system files.
- Restore corrupted files with the tool.
Fixing 503 Service Unavailable Error for Site Owners
If you have access to the server, you can try the following options to fix HTTP 503 error and restore access to the website.
9. Reboot the Web Server
This is the simplest solution and by restarting the server, you may immediately fix the HTTP 503 error. It could be caused by data bottleneck and crashed programs. You can bring them back to normal by rebooting the server.
10. Check Server Resource Usage
Rebooting the server is generally not possible on a shared hosting environment, as many other sites will get affected. The possible way is to analyze your server log file to find what is going wrong. Most of the times, the servers have limit in number of executions, CPU, RAM and PHP memory limit. If your site exceeds any of these limits, it will result in temporary service termination of your hosting account.
You can discuss with your hosting company to resolve the situation. Also check whether you have autoscale option to automatically upgrade the CPU and RAM when spike in usage happens.
11. Check Unauthorized Updates
Content management systems, including WordPress, download and install updates automatically. Unfortunately, new updates can be incompatible with third party plugins, widgets and themes. It should be quite easy to investigate updates that may cause the error. Check when the error first occurred and find out the closest update. Undo these updates and check that resolves 503 service unavailable problem.
12. Check Your Last Activity
Similar to auto update, you may also updated some plugins, theme or backend files. Just missing a comma or adding a dot in configuration files will result in 503 service unavailable error.
13. Check Firewall Configuration
Firewall is the gatekeeper of your server and it blocks potentially harmful data stream. Firewall decides which traffic is malicious or safe. However, overly restrictive firewall configuration may prevent genuine and critical data stream from getting through. So, check whether your firewall labels safe data traffic as false positives. And consult your user manual to make the configuration less restrictive.