The 503 Service Unavailable error is an HTTP status code that means the website’s server is simply not available at the moment. Most of the time, it happens because the server is too busy or because maintenance is being performed on it.
Are you the Webmaster? See the section Fixing 503 Errors on Your Own Site further down the page for some things to look at if you’re not sure what to do.
A 503 error message can be customized by the website it appears on, or by the server software that generates it, so the ways you might see it vary greatly .
How you can see the 503 error
Below are the most common ways you might see the “service unavailable” error:
503 Service Temporarily Unavailable
Http/1.1 Service Not available
HTTP 503 server error
Service Unavailable - DNS Failed 503 Error
HTTP503
HTTP Error 503
Error 503 Service not available
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503 Service Unavailable errors can appear in any browser on any operating system, including Windows 10 again through Windows XP, macOS, Linux, etc…even on your smartphone or other non-traditional computers. If you have Internet access, then you might see a 503 in certain situations.
The 503 Service Unavailable error is displayed within the browser window, just like web pages.
Sites that use Microsoft IIS can provide more specific information about the cause of a 503 Service Unavailable error by suffixing a number after 503 , as in HTTP Error 503.2 – Service Unavailable , which means Concurrent Request Throttling exceeded . See More ways to see a 503 error near the bottom of the page for the full list.
How to fix the 503 service unavailability error
The 503 Service Unavailable error is a server-side error, which means that the problem is usually with the website’s server. It’s possible that your computer is having some kind of problem that is causing the 503 error, but it’s not likely.
However, there are a few things you can try:
- Try again from the address bar by clicking the reload/refresh button, or by pressing F5 or Ctrl+R .
Although the 503 Service Unavailable error means that there is an error on another computer, the problem is likely only temporary. Sometimes trying again will work.
If you see a “503 Service Unavailable” error message when paying for an online purchase, be aware that multiple payment attempts may end up creating multiple orders and multiple charges. Most payment systems, and some credit card companies, have protections against this sort of thing, but it’s still something to be aware of.
- Reboot your router and modem, and then your computer or device, especially if you see the “Service Unavailable – DNS Failure” error.
Although the 503 error is still most likely the fault of the website you’re visiting, it’s possible that there’s a problem with your router’s or computer’s DNS server settings, which a simple restart of both might fix.
If restarting your computer did not fix the 503 DNS Failure error , there may be temporary problems with the DNS servers themselves. In this case, choose new DNS servers from our list of free and public DNS servers and change them on your computer or router. See How to Change DNS Servers if you need help.
- Another option is to contact the website directly for help. There’s a good chance the site administrators already know about the 503 error, but letting them know, or checking the status of the problem, isn’t a bad idea.
Check out our list of website contact information for contact information for the most popular websites. Most of the sites have support based social media accounts and some even have phone numbers and email addresses.
If the website giving the 503 error is popular and you think it may be completely down, plug the URL into isup.me or IsItDownRightNow? A clever search on Twitter can also give you the answer. Try searching for #websitedown on Twitter, replacing website with the name of the site, as in #facebookdown or #youtubedown. A blackout at a large site will usually generate a lot of conversation on Twitter.
- Come back later. Since the 503 Service Unavailable error is a common error message on very popular websites when a large spike in visitor traffic (that’s you!) is overwhelming the servers, simply waiting for it to come out is often your best bet. best bet. Frankly, this is the most likely solution for a 503 error. As more and more visitors leave the website, the chances of the page loading successfully increase.
Fix 503 errors on your own site
With so many different web host options, and even more general reasons why your service might be unavailable , there’s no easy “thing to do” if your site is giving your users a 503.
That said, there are certainly some places to start looking for a problem…and then, hopefully, a solution.
Start by taking the message literally: has something crashed? Restart any running processes and see if that helps.
Beyond that, look at the not-so-obvious places where something might have hiccuped. When applicable, look at things like connection limits, bandwidth throttling, general system resources, security devices that may have been activated, etc.
In what is very likely to be a “double-edged sword” for your website, it may suddenly be very, very popular. Getting more traffic than your site was built to handle almost always triggers a 503.
However, the 503 error could also be the result of a malicious Denial of Service (DoS) attack. If so, it would be wise to contact the company that hosts your website, to discuss steps that can be taken to reduce the likelihood of it happening again, or to better prepare for another one in the future.
An unintentional denial of service attack can even occur, in which a virus on the server is sucking up usable system resources and slowing down the server to the point of causing a 503 error.
More ways to see a 503 error
In Windows applications that access the Internet natively, you may see a 503 error with the error HTTP_STATUS_SERVICE_UNAVAIL , and perhaps also with a The service is temporarily overloaded message .
Windows Update may also report an HTTP 503 error, but it will show up as error code 0x80244022 or with a WU_E_PT_HTTP_STATUS_SERVICE_UNAVAIL message.
Some less common messages include 503 Over Quota and Connection Failed (503) , but the troubleshooting above applies anyway.
If the website reporting the 503 error is running Microsoft’s IIS web server software, you might get a more specific error message like one of these:
IIS 503 Errors Status Code Reason Phrase 503.0 Application Pool Unavailable 503.2 Concurrent Request Limit Exceeded 503.3 ASP.NET Queue Full 503.4 FastCGI Queue Full
More information about these IIS-specific codes can be found on Microsoft’s page The HTTP Status Code in IIS 7.0, IIS 7.5, and IIS 8.0.
Errors like 503 Service Unavailable
The 503 Service Unavailable error is a server-side error, so it is closely related to other server-side errors such as the 500 Internal Server Error, the 502 Bad Gateway error, and the 504 Gateway Timeout error, among others.
There are also various HTTP status codes on the client side, such as the common 404 Not Found error, among others.