HTTP response codes, particularly those that display error codes, can be difficult to deal with. One such error code that can prove difficult to fix is the 502 Bad Gateway error. That’s because it’s usually a result of a broad and complex relationship between the client, the server, the web program, and many other factors outside the web service.
As such, pinning down the exact cause of the 502 Bad Gateway error can be difficult and frustrating. If you’re a user trying to access a site that is showing this problem or a web developer trying to figure out why your site keeps on throwing up this error, read on to find out what causes this problem and how you can fix it.
Also read: Top 10 Common WordPress Errors (and How to Fix Them)
What Is 502 Bad Gateway Error?
Every time you visit a website, your browser sends a request to a web server. The web server receives the request and processes it, then “returns” the requested information along with an HTTP status code and HTTP header. A working connection will return a 200 HTTP status code and the web content to be displayed on your browser. Usually, you don’t see the HTTP status code displayed unless there is a problem with communication between the web servers.
The 502 Bad Gateway error is one of the HTTP status codes. This error code indicates that the web server you have connected to, while acting as a gateway for relaying information from another server, received an invalid (bad) response from that other server. It’s often triggered when there are communication issues between the upstream (or origin) server and the gateway server.
What Causes the 502 Bad Gateway Error?
A 502 error can show up due to many reasons. Here are just a few.
1. Server Overload
One of the main causes of the 502 Bad Gateway error is server overload. If the server is overloaded, you’re likely to often get the bad gateway error. Note that a server can crash if it has exhausted its memory. High traffic on the site can also trigger the 502 error.
2. Network Errors
Routing problems, DNS issues, and ISP-related issues can also trigger the 502 Bad Gateway error. Problems with your home-networking equipment can cause your browser to think there are issues with online servers, even when there aren’t any.
3. Faulty Programming
If there’s an error in a website’s code, it may prevent requests from being handled correctly. This may prompt the 502 Bad Gateway error to show up.
4. Improper Firewall Configuration
By monitoring network traffic, a firewall acts as a gatekeeper that decides which traffic is safe and which one could be malicious. It thus blocks all the potentially harmful traffic. In some cases, especially for users that rely on Content Delivery Networks (CDNs), automatic firewalls can perform false positives and end up preventing critical traffic from getting through.
5. Server Software Timeouts
The 502 Bad Gateway error can also be triggered when a web server takes too long to complete the request, causing a caching tool to reach its timeout values.
How to Diagnose a 502 Error
Even though a 502 Bad Gateway error is often caused by issues between online servers, there are steps you can take on your end to try to fix the problem. Here are some possible fixes to try.
1. Check If the Website Is Down for Everyone
Whenever you’re experiencing a 502 error, it’s important to first check whether the site is down for everyone or just you. One of the online tools you can use that will let you know whether other users are having problems accessing the site is Down for everyone or just me.
Another great online tool you can use, which is also pretty easy to use, is Is It Down Right Now? Just plug in the site’s URL, and you’ll be able to check its server status.
This one will even show you the last time the server was down. If the site is down for everyone, there isn’t much you can do. But if the tool shows you that the server is up, then the problem is probably on your end. Try some of the tricks described below.
2. Reload Your Website
At times your server can take longer to respond due to increased traffic. If that’s the case, refreshing the page might do the trick. If this fixes the issue, then the problem was temporary, and you shouldn’t worry much about it.
However, if this doesn’t fix the problem or the problem occurs frequently, then you will want to delve deeper, as there may be something else that needs to be fixed.
3. Disable Firewall or CDN
If you’re using a website firewall or CDN service on your website, then it’s possible that their servers are acting up. To figure this out, you’ll need to temporarily disable the CDN. Doing so will remove the extra layer standing between your browser and the hosting server.
Your website will now load directly from your server, and if the issue was caused by a firewall/CDN service, you’ll know. If this fixes the problem, you can then consult your CDN service provider for assistance.
4. Clear Your Browser Cache and Cookies
Outdated cached files or cookies can also cause the 502 error. Removing these cached files, then reloading the website could solve the problem.
If you don’t want to clear all the cookies, you can first try removing the cookies related to the site where you’re getting the 502 error.
5. Clear DNS Cache
A 502 Bad Gateway error can also result from local DNS issues, such as the DNS unable to resolve the hostname or the right IP. The solution here is to flush the DNS cache. To do so, open the command prompt (Win + R), type cmd in the text box, hit Enter, and then type the following command:
ipconfig /flushdnsIf successful, a “Successfully flushed the DNS resolver cache” notification will be displayed.
This should fix the problem if the DNS cache was the culprit.
6. Consult Your Hosting Company
One of the main reasons why a 502 error occurs is due to issues with your web host. At times a request can get canceled by the server if it takes too long. That’s because most hosts implement what they call a “kill script.” It’s this kill script that terminates a request if it takes longer than usual so as to prevent that query from taking a site down or affecting other users.
If your host is running aggressive kill scripts, you’re likely to encounter frequent 502 error reports. You could also get 502 error reports if your host servers are down or unreachable for some reasons. Checking with your host can help to identify the cause of the error and probably come up with a solution.
7. Restart Your Computer / Networking Equipment
Some issues with your computer, particularly issues that affect how it connects to your network, could also cause the 502 error. A simple restart should fix the problem. Issues with your networking devices – modem, routers, etc. – could also be the culprit. In such cases, a simple restart should get you back online.
8. Try Another Browser
As mentioned earlier, your browser might think there is a real issue with the servers even if there isn’t one. Try to open the site with another browser. If an alternative browser doesn’t show a 502 Bad Gateway error, then you’ll know the original browser is the culprit.
Wrapping Up
502 Bad Gateway errors are very common, and while these errors are server related, there is still something you can do on your end to fix the problems. We hope these tips will help you resolve future 502 errors and have a seamless browsing experience.
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