The 503 Service Unavailable error is an HTTP status code that means the web site’s server is simply not available right now.
The Web server is currently unable to handle the HTTP request due to a temporary overloading or maintenance of the server. The implication is that this is a temporary condition which will be alleviated after some delay. Some servers in this state may also simply refuse the socket connection, in which case a different error may be generated because the socket creation timed out.
How You Might See the 503 Error
Here are the most common ways you might see the “service unavailable” error:
- 503 Service Unavailable
- 503 Service Temporarily Unavailable
- Http/1.1 Service Unavailable
- HTTP Server Error 503
- Service Unavailable – DNS Failure
- 503 Error
- HTTP 503
- HTTP Error 503
- Error 503 Service Unavailable
503 Service Unavailable errors can appear in any browser in any operating system, including Windows 10 back through Windows XP, macOS, Linux, etc…. even your smartphone or other nontraditional computer. If it has internet access, then you could see a 503 in certain situations.
The 503 Service Unavailable error displays inside the browser window, just as web pages do.
Cause of 503 Service Unavailable Errors
Most of the time, a 503 error occurs because the server is too busy or because there’s maintenance being performed on it.
How To Fix the 503 Service Unavailable Error
The 503 Service Unavailable error is a server-side error, meaning the problem is usually with the web site’s server. It’s possible that your computer is having some kind of problem that’s causing the 503 error but it’s not likely.
Regardless, there are a few things you can try:
- Another option is to contact the website directly for help. There’s a good chance that the site’s administrators already know about the 503 error but letting them know, or checking the status on the problem, isn’t a bad idea.
- Retry the URL from the address bar again by clicking the reload/refresh button or pressing F5.Even though the 503 Service Unavailable error means that there’s an error on another computer, the issue is probably only temporary. Sometimes just trying the page again will work.
- Restart your router and modem, and then your computer or device, especially if you’re seeing the “Service Unavailable – DNS Failure” error.While the 503 error is still most likely the fault of the website you’re visiting, it’s possible that there’s an issue with the DNS server configurations on your router or computer, which a simple restart of both might correct.
- Come back later. Since the 503 Service Unavailable error is a common error message on very popular websites when a huge increase in traffic by visitors (that’s you!) is overwhelming the servers, simply waiting it out is often your best bet.
Frankly, this is the most likely “fix” for a 503 error. As more and more visitors leave the website, the chances of a successful page load for you increases.
503 errors in the HTTP cycle
Any client goes through the following cycle when it communicates with the Web server:
- Obtain an IP address from the IP name of the site (the site URL without the leading ‘http://’). This lookup (conversion of IP name to IP address) is provided by domain name servers (DNSs).
- Open an IP socket connection to that IP address.
- Write an HTTP data stream through that socket.
- Receive an HTTP data stream back from the Web server in response. This data stream contains status codes whose values are determined by the HTTP protocol. Parse this data stream for status codes and other useful information.
This error occurs in the final step above when the client receives an HTTP status code that it recognises as ‘503’.