So have you faced the backend fetch failed Error 503 at any point in life? Well, if you have there here’s a brief description to start with. The error 503 backend fetch failed signifies that the server of a certain website is not being able to respond. 

The error code comes up in the form of a pop-up of HTTP (Hypertext Transfer Transfer Protocol). It is rather a bit easier for developers to pinpoint exactly where the issue triggers from when a website is not responding. 

CentOS Web Panel: What Is It? 

CentOS Web Panel is known to be a web-based control panel that deals with the management of a server. It plays a key role in enhancing the performance of the server. Alongside, it also enhances the speed quality of the web-based applications. But, to do so, it often uses the functions of a program called Varnish cache. 

Now, here’s the problem. Using Varnish Cache may often lead to the 503 backends fetch failed error. This happens as certain configurations fail to match due to settings mismatch.  Now you may ask what varnish cache is. Well, Varnish cache is something that is used to decrease the loading time of a website. Usually, it is known as a reverse proxy. 

To ensure fast loading time, varnish cache goes to the back end server so that it can cache. After that, it stores the web pages. Once that is done, the Varnish cache does the rest of the relevant services. 

Error 503 Backend Fetch Failed: Reasons Behind It!

There are some key reasons why you’d face the 503 backend fetch failed. Here’s why:

1. Memory Issues

If a website is being accessed by many people at the same time, then the servers are getting a high load on it. This is because the requests are getting on the queue. Now, to initiate a response, memory is needed. If there is not enough or sufficient amount of space in memory, the connection establishment will fail with the servers of the backend. 

2. Invalid Configurations Of Varnish Cache

If there is a configuration error in the Varnish Cache, then most likely you’ll be facing the issue. If the Apache and the Varnish Cache are working on port 80 together, or if the configuration of Varnish’s Internal Protocol is not being listened to. 

Here’s How You Can Resolve Error 503 Backend Fetch Failed!

Now that you have a clear idea of what’s 503 backend fetch failed, go through the following methods to resolve the problem easily:

Method 1: Update/Refresh Website Page

At times like this, it is always advisable to refresh the web page as it solves most of the issues. So, here’s what you can try doing:

The first thing you can do is go to the website and then simply log in. To gain full access to the website, you’d have to navigate further to the Host Server. For that, use Filezilla which happens to be an FTP client. 

Once that is done, visit the Magneto website and then pull its registry. After that, go to the account that is named “Maintainance Flag”. Now ensure that you erase the name. 

The error should be resolved by now. To check, refresh the web page of Magneto. If the error still persists then refresh again using the F5 key on the keyboard. 

Method 2: Reboot

Rebooting the device may solve a lot of internal issues. For example, if you reboot the framework, then issues related to the Domain name Server (DNS) will be solved. As a result, the error 503 backends fetch failed error may get resolved too. 

Method 3: Get In Touch With Administrators

One of the most effective solutions is to get in touch with the administrators of the website. The administrators already have an idea of the error 503. However, it is essential that you explain the full status of the error. 

Go through the website and you’ll find effective means of contacting, such as a social network system for the support team, a phone calling option as well as an email address. 

Method 4: Analyse Total Use Of Memory 

As mentioned previously, Varnish Cache deals with maintaining a stable load during a web page request. But, that obviously implies that for each and every request, Varnish will require memory. So more requests mean more memory used. 

To resolve this factor, you’d have to get in touch with the Hosting Support Engineers. Then the next thing to do is get an idea of how many visitors are visiting the website on an average count. Based on that, check the amount of memory is being used. 

If you come to find that there is a load on the memory, then it is advisable to add extra memory for the varnish cache. Doing this will prevent difficulties. 

Method 5: Check For Varnish Interface

To ensure that there is no issue with the interface o Varnish. Do the following steps:

Make adjustments to the port of Varnish. Make sure the IP address is not incorrect. And also check other domains that belong to the CentOS Web Panel. If you see that the server is getting overloading even after proper configuration in Varnish, then disable it. 

First, go to the CentOS Web Panel. Then, sign in to it. After that, go to the option called “Apache Settings”. Now, change the webservers by transforming. 

Method 6: Delay & Try Again

Another thing you can try doing is to wait. Because the server gets requests often which is why it gets overloaded. Wait for a certain period of time and then try connecting again. 

If 1 out of 10 visitors decides to stop accessing the website, then also the server will have 1 out of 10 reasons to not cause an overload. 

Method 7: Check Plugins

Another thing that could trigger the 503 backends fetch failed error is the Varnish Plugin. Check if the varnish plugin is working or not. 

Method 8: Reset Network Connection

This idea may have been overlooked. Often, the network connection remains one of the underrated reasons for such issues. Or, if there is some issue with the Domain Name Server. 

In that case, it is advisable to reset the router and then start it again.

Method 9: Windows Repairing

There’s one last thing you can try doing. And that is, repairing windows because the problem may be at your end. Here’s how to do it:

Go to the “Start” section and then search for “Advanced Startup Options”. Then click on the result. Now using the installation disk, boot the system. Then, click on the “Next” button. After that choose the option called “Repair”. 

Now, wait until the system is booted. Then click on the option called “Troubleshoot”. After that, choose the option called “Advanced Options”. Then finally go for the option called “Startup Repair”. 

Now Windows will go through the repairing procedure. Make sure you do not interrupt the process of repairing by switching off the system. Once that is done, try connecting to the Magneto Website server page and see if you get the 503 backend fetch failed error or not.