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What’s a 503 service unavailable error?

Maria LeLaurin
Maria LeLaurin

May 20, 2019 — 3 min read

How to troubleshoot one of the most common error messages you'll see online.

If you’re seeing a 503 service unavailable error message, it can have you scratching your head wondering what you’ve encountered. It even feels somewhat generic because, after all, what does “service unavailable” really mean? The upside is it’s only temporary, so you can pick up where you left off relatively soon. You can also do a few things to troubleshoot the issue, but chances are the problem is coming from the server itself.

A 503 error is different from a 500 internal server error

When a server is overloaded or down for maintenance, you’ll likely get a 503 service unavailable error. It’s just one of many HTTP status codes. It differs from a 500 internal server error because the 500 error means there’s an unspecified issue preventing the server from handling a request, while a 503 means that the server is running properly but it’s temporarily out of commission. You may also see a 503 appear as:

  • HTTP error 503
  • 503 error
  • 503 service temporarily unavailable
  • error 503
  • 503 service unavailable
  • service unavailable – DNS failure

Three main causes of a 503 error

Unlike some error messages that have a lengthy list of causes, the 503 error is generally due to one of only three scenarios.

1. Server maintenance

Much like your car, a server gets routine maintenance to keep things running smoothly. It could be undergoing general updates and enhancements for user experience, going through important backups or adding database security.

2. Server overload

Too much traffic can overload a server. You’ve probably experienced this around the holiday season when you and millions of other people are shopping on the internet. The server can also become overloaded if the site’s content has outgrown its resources. Another possibility for server overload is malware or spam attacks.

3. An incorrect DNS server configuration

A domain name server is the go-between for computers and computer users. Essentially, it translates domain names into IP addresses. Malware or spam can change DNS settings.

Try these simple troubleshooting tips

As a general rule, a 503 service unavailable error comes from the server side and not from your side. That said, here are a few quick and easy ways to test things out just to be sure. For efficiency, take these steps in order as the first one may be the only one you need to do.

  1. Refresh the page – As with a lot of things, sometimes a simple refresh works wonders. You can either use the refresh button in your browser or the F5 button on your keyboard. If you’re in the middle of making a payment, be careful since you might get charged twice once you hit the refresh button.
  2. Restart or reboot your device – The 503 error message may be due to your network settings. Simply restart your computer or device and don’t forget to reboot your modem and router. This shouldn’t take more than a few minutes to complete.
  3. Give it some time – You know the saying: patience is a virtue. Give it a few hours for site traffic to ease up a bit or for repairs to be made. You can always spend time on other sites while you wait.
  4. Notify someone who can take action – You can find contact information on the site or you can go through the company’s or organization’s social media such as Twitter or Facebook.

Take the confusion out of error messages

Every hour of every day, people get served error messages while on the internet. Most of them, including a 502 error and a 504, can be easily resolved. You can rely on us to provide the information you need.