WHAT IS A 502 BAD GATEWAY ERROR

502 Bad Gateway is is an error that occurs when a proxy server receives an invalid response from the inbound server.

1.   HTTP Error 502 Bad Gateway
2.   502 Error
3.   502 Bad Gateway
4.   502 Proxy Error
5.   HTTP 502
6.   502 Bad Server Error
7.   502 Bad Gateway NGINX

You must often find some of those errors. They have the same meaning, that is the proxy server receives an invalid response from a server.

An error usually occurs due to a communication problem or error among the server. There are some factors which cause the 502 Bad Gateway error:

1) The server is overloaded

2) Crash on an upstream server

3) The browser cache is down

4) There is a bug on a script

5) CDN (Content Delivery Network) is down

6) There is an error on the network or router device

7) There is an error on the Domain Name System (DNS)

502 Bad Gateway is not a fatal error or need to be worried. This error will not ruin the system on your sites. This kind of error usually happens because of the overload, so it needs times to make your sites run normally.

If it doesn’t bring any result after you finish reloading it, then you can clear your cache browser. It turns out that the amount of cache which piles up can cause the 502 Error. Therefore, if it happens, it is suggested to you to clear the cache browser that already piles up.

The problem or trouble on the network can cause a 502 Error. Therefore, if you clean the cache browser and it doesn’t work, you can try to restart the networking. You only have to pull out the power cable on the network device and wait a few seconds, then replugging the cable. After that, open the website again to verify whether the error has been solved or not.

CDN or Content Delivery Network is a service which can display the WordPress site that you have, so it can optimize the site's performance.

DNS is an important part of the internet. If a domain can’t display the valid IP’s address, it can lead to 502 Bad Gateway Error. Therefore, it must be verified whether the DNS is changed which leads to the error.

If you are using windows, you can open the command prompt, then type ipconfig and enter it. While, if you are using Mac, you can type dscacheutil -flushcache on the terminal.

By switching the DNS on the computer or the other router, it can cause an error. You can use a free standard DNS server such as Verisign or Google.

You can try to check the plugin and extension when the error gateway happens. Sometimes, the error that is caused by the caching plugin can cause a 502 Error. The simple way to check it is that by shutting down all of the plugins temporarily.

If a problem or an error happens, you can try to change the theme of your website. After that, try to refresh the error page. If the page is loaded successfully and there are no other problems, then it can be concluded that the problem can be caused by the theme that is used.

If the error appears after you have changed something on your website, it means that the problem is on the website. The way to fix is that by checking the error log. In WordPress, you can activate the error log by adding define (‘WP_DEBUG’,true) on wp-config.php.

Software that is rarely updated can cause the error gateway. In avoiding the error which is caused by rarely updating software, it is suggested to update it when the software needs an update. It is for avoiding the error from a software that has never been updated.

The Error also can be caused by the unresponsive server. If it turns out that your online server can use trace route or ping test to detect what happens on the server.