What is a 502 Bad Gateway? Complete Explanation also Meaning and Reason

 

Some of you may have seen the words "502 Bad Gateway" displayed while using your computer. "502 Bad Gateway" is an error message indicating a problem with the communication status of the website's servers. In this article, we will go over the causes of "502 Bad Gateway" and how to deal with it.

 

What is a 502 Bad Gateway?

As mentioned earlier, "502 Bad Gateway" is an error code that is displayed when there is some kind of communication problem due to a communication failure between the servers. Since there is more than one cause, it is necessary for the service provider to identify the cause from different perspectives and act to remedy the same.

There are several error codes besides 502 Bad Gateway. Other articles also state specific error codes. 

502 Bad Gateway is not infected with virus

If you get a 502 Bad Gateway, it's usually a problem with your service provider. Also, some people get the misconception that they are infected with some kind of virus, but this is a server side error and not a virus.

Causes of 502 Bad Gateway

Here, we will explain the possible causes of "502 Bad Gateway". In the end, the reasons are as follows.

• Server capacity exceeded (punctuation)
• Temporary reach concentration
  

I will explain each one in turn.

• Server Exceeded Capacity (puncture)
  

  The first reason is that when the number of accesses exceeds the capacity of the server, the server cannot cope with the load and "502 Bad Gateway" is displayed. For example, if you are using a low-cost rental server, or if the site is large and the number of accesses increases, the server may become overwhelmed.
  
  So, unless you change the server to a server that can withstand that number of accesses, this will keep happening.
  
  Also, if the server fails, Wait for the official recovery information as it will put more load on the server.
  

• Temporary Reach Concentration
  

  The second reason is overload on the server due to temporary access concentration. For example, this can happen when multiple users are spread over SNS and access is temporarily concentrated. In many cases, when the access concentration is eased it will return to the original position. In other words, it is necessary to take prompt action as the problem can be recovered by restarting the server.

Disadvantages of 502 Bad Gateway

Here, we will explain the disadvantages of "502 Bad Gateway". Lastly, it has the following disadvantages.

• Opportunity Loss Happens as a Business
• Opportunity loss can also result in loss of sales

Let's look at each one in turn.

• Opportunity Loss Happens as a Business
  

  As the site grows, if the number of accesses exceeds the capacity of the server, a "502 Bad Gateway" will be displayed. In other words, if an error persists despite having access, it will be a lost opportunity. If access errors occur frequently, server specifications may not match the scale of the site, so we recommend reviewing the server configuration and plan.
  
  Also, by introducing a "server monitoring tool" as a preventive measure, it may be possible to detect errors early, so always create a preventive system.

• Loss of opportunities can also result in loss of sales
  

  There are also disadvantages such as loss of sales due to opportunity loss. Therefore, managers must take measures to prevent opportunity loss. If you are an administrator, restarting the server one more time can be an effective countermeasure. Also, if necessary, review adding servers when analyzing the number of accesses.
  
  Errors in the 500 range indicate a problem on the part of the site administrator, and immediate measures are needed to prevent loss of access opportunities. Basically, the solution is to check the server you are using, so contact us as soon as possible. 
  
   
   

502 Bad Gateway cannot be handled by the User

"502 Bad Gateway" cannot be dealt with on the user side. In case of temporary server load, this can be resolved by doing super reload and clearing the cache. However, there is usually no solution on the part of the user, as the cause is usually attributed to the administrator's server that was accessed.

If "502 Bad Gateway" is displayed when accessing the same website on another line or terminal, wait for recovery as it is a server-side failure. 

How to deal with 502 Bad Gateway as an Administrator

As an administrator, there are four main ways to deal with a 502 Bad Gateway. The four methods are as follows.

• Check if There is a Problem on the Server Side
• Check Mirror Dns Servers
• Server Log
• Check if There is a Problem With the Repair

I will explain each one in turn.

• Check problems on server side
  Basically, websites are hosted on multiple servers and third party hosting providers. Therefore, if the server is down, for some reason such as maintenance, a "502 Bad Gateway" error page will be displayed. In that case, you have no choice but to wait until the problem is resolved due to server maintenance or error.
  
  Also, if you use SNS etc, in similar case 502 could be bad gateway and how to solve it can be explained. For example, search for "502 Bad Gateway (Server Name)".
  
  
• DNS server mirroring
  Secondly, the 502 Bad Gateway error can be caused by your DNS server settings. A DNS server, also known as a name server, is a server that translates domain names and IP addresses.
  
  If you recently changed your IP address or domain, it may not be reflected on the DNS server. It may take some time for the changes to be reflected, so you will have to wait until the reflection is complete.
  
  
• Check Server Logs
  The server log contains a status that allows you to see if the server is running normally. Therefore, you can check the cause of the error by checking the server logs. For example, we use Google Analytics to review traffic and check for changes to our site and servers when traffic is low. If you get a setting error, restore it and try to recover before changing the setting.
  
  
• Make sure there are no problems with the repair.
  Lastly, if "502 Bad Gateway" is displayed after a design change such as a site upgrade, it is possible that the newly replaced part is causing the error. Let's focus on the implementation of the parts affecting the server, such as PHP and JavaScript.

How to prevent 502 Bad Gateway

There are two ways to prevent `502 Bad Gateway': ``Basically, increase the server specifications'' and ``Check if there are any problems with the repair before publishing it. Let's look at each one in turn.
 

Raise Server Specs

If the "502 Bad Gateway" is resolved by temporarily reloading the page or leaving some time, it is because of the concentration of access, so the communication timeout is the reason. Therefore, in order to eliminate the overload on the server, it is necessary to increase the performance of the server.

Basically, you can check the load status of the server from the control panel, so consider changing the server plan or switching servers after calculating the required specifications. In addition, if the reason is timeout due to excessive access, it will not be fixed until the server is strengthened, so let's strengthen the server after fully confirming the reason.

As a side note, errors from apps can also be displayed. If "502 Bad Gateway" occurs after you deploy a new app or update an existing app, there is a bug in the app source. Please check the part of the application that has changed and fix it if you find a bug.

Make sure there are no problems with the revision before publishing

As mentioned above, if you modify your site, make sure there are no issues. Although we are careful about the repair, if there is a problem with the firewall settings, it will be considered an attack on the server, hence a "502 Bad Gateway".

A firewall acts like a "firewall" for a website, protecting it from malicious users and distributed denial of service (DDoS) attacks. So, if you check your firewall settings and find any issues, fixing them will eliminate the error. Also, be sure to take regular backups in case of an attack.  

Summary

In this article, I explained the causes of "502 Bad Gateway" and how to deal with it. Lastly, there is more than one reason for "502 Bad Gateway", so check the error code and take action. Basically, when you see the "502 Bad Gateway" error, you wait for it to be fixed. On the other hand, administrators need to solve the problem as soon as possible, so please refer to this article to prevent it from happening.