fix HTTP error 503 service unavailable

HTTP errors usually come in the form of status codes which are standard response codes that help you identify the cause of the problem given by a website server when either a web page or other resource fails to load properly while online.

Whenever you get an HTTP status code, it comes with the code itself, and the corresponding explanation such as HTTP error 503: The service is unavailable.

Something else you may want to keep in mind is that each of these codes, also known as browser errors, Internet error codes or Internet connection errors have their groups.

The HTTP 503 error falls under the 5xx server error group of HTTP status codes. They usually indicate that the web page or resource request is understood by the server, but the latter cannot fill it for one reason or another.

However, the HTTP error or status codes shouldn’t be confused with Device Manager errors or system error codes, because the latter are associated with different errors and meanings altogether.

When you get HTTP error 503, this usually points to the website’s server, which may have been compromised by an overload (temporarily) or it is too busy, or there’s some ongoing such as scheduled maintenance.

Fortunately, this error comes up, there are fairly quick solutions to fix the issue and get the website back online.

What is HTTP error 503 and how can I fix it?

  1. Preliminary checks
  2. Close your proxy server
  3. Start the destination application pool
  4. Change Load User Profile
  5. Change Identity in Application Pool

1. Preliminary checks

Whether the issue is with the server or your computer, there are some things you can try and check before fixing HTTP error 503: The service is unavailable. You could start by retrying the URL from the address bar by reloading or refreshing the page.

You can also restart your modem and router, then restart your computer or device – this is especially so if you see the ‘service unavailable – DNS failure’ message. If this doesn’t fix the error 503 DNS issue, pick new DNS servers and change them on your PC or router.

Check with the website itself directly for assistance as they may be aware of the error 503, so they may let you know if it is an issue that’s with everyone, not just you. Sometimes waiting it out is the easiest fix to this error.

2. Close your proxy server

Perhaps you use a VPN or a proxy server, in which case, you need to check whether the connection is working the way it should, or properly. If the proxy server is down, then you may end up getting the HTTP error 503: The service is unavailable message.

This usually happens with free proxy servers, but if you do not use a proxy server, you can disable it and then try to open the website that is showing the HTTP error 503 the service is unavailable.

3. Start the destination application pool

If the application pool of the corresponding web application is stopped, or disabled, it causes the website to show HTTP error 503: The service is unavailable. Additionally, any misconfiguration in the application pool or site settings can cause the error on the site. Process crashes also happen due to incorrect application logic.

Sometimes the user account related to the user identity of an application pool can be locked or has an expired password, or even inadequate privileges which tamper with the functioning of the website.

If the application pool runs out of RAM or other resources, it can crash and lead to HTTP error 503, plus server migrations also lead to such errors.

If HTTP error 503 the service is unavailable is caused by a stopped application pool, starting it would resolve the issue.

  • Click Start
  • In the search bar, type Windows Features
  • Select Turn Windows Features on or off

http error 503 the service is unavailable

  • Locate Internet Information Services and check the box – this will install everything you need to use IIS

http error 503 the service is unavailable

  • Go to Control Panel

http error 503 the service is unavailable

  • Select View By and click Large Icons
  • Click Administrative Tools

http error 503 the service is unavailable

  • Find IIS Manager and double click on it

http error 503 the service is unavailable

  • Select Application Pools node

http error 503 the service is unavailable

  • Right-click on DefaultAppPool to check the status. If it is stopped, start it. If it is running, restart it and see if HTTP error 503 the service is unavailable is gone.

http error 503 the service is unavailable

4. Change Load User Profile

If the problem is the DefaultAppPool, change the ‘Load User Profile’ to false by doing the following:

  • Go to Control Panel
  • Select View By and click Large Icons
  • Click Administrative Tools

http error 503 the service is unavailable

  • Find IIS Manager and double click on it

http error 503 the service is unavailable

  • Select Application Pools node

http error 503 the service is unavailable

  • Click on DefaultAppPool to select or highlight it

http error 503 the service is unavailable

  • On the right pane, select Advanced settings

http error 503 the service is unavailable

  • Find Process Model

http error 503 the service is unavailable

  • Go to Load User Profile

http error 503 the service is unavailable

  • Change from True to False

http error 503 the service is unavailable

5. Change Identity in Application Pool

  • Go to Control Panel
  • Select View By and click Large Icons
  • Click Administrative Tools
  • Find IIS Manager and double click on it
  • Select Application Pools node

http error 503 the service is unavailable

  • Find the correct Application Pool for your website and click on it
  • Click Advanced Settings

http error 503 the service is unavailable

  • Under Process Model, select Identity and change it, then enter a new user and password

http error 503 the service is unavailable

  • Click on your Application Pool again and select Recycle to restart it.

FAQ: Learn more about HTTP error 503

  • What can cause error 503?

Error 503 occurs when the server of the website you’re visiting is overwhelmed due to a much larger number of requests than it can handle or is having maintenance performed on it.

  • How do you fix error 503?

Here are the best troubleshooting methods to fix error 503:

  1. Reload the website
  2. Restart your modem and your computer
  3. Clear the browser cache
  4. Check your proxy settings
  5. Restart the DefaultAppPool 
  • What does service temporarily unavailable mean?

The error message Service temporarily unavailable indicates the server is not available either due to overloading issues or scheduled maintenance work. This is only a temporary issue, the service should get back online once the problem has been solved.

Editor’s Note: This article continues on the next page with more solutions to fix error 503 on specific services. Meanwhile, take a look at our wide collection of guides for more tips and tricks on how to enjoy the best possible browsing experience on PC.