Error 503 Backend Fetch Failed [4 Solutions]

The 503 no service error is an HTTP status code that points out that the website’s server is not functioning. It is not restricted to any particular operating system. This error can even occur in smartphones and nontraditional computers.

It interrupts your browsing experience, and I get how bad this can be. Therefore, I have arranged a couple of possible solutions for this error. This guide will review what this error is, its causes, and possible solutions for it.

The error 503 is one of the HTTP status codes that the website’s servers provide to enable users to troubleshoot server issues. These status codes are response codes and are usually customized by the website it appears on. So, you may see it in different forms as follows:

Http/1.1 Service Unavailable 
HTTP Server Error 503 
503 Service Unavailable 
503 Service Temporarily Unavailable 
HTTP 503 
HTTP Error 503 
Service Unavailable – DNS Failure 
503 Error 
Error 503 Service Unavailable 

This error can also come with the message The service is temporarily overloaded in Windows applications.

How to Fix the Error 503 Backend Fetch Failed

There are several solutions that you can try out if you want to fix the error 503. You will most often just need to wait it out, especially when the error occurred due to increased traffic on the website, caused by visitors like you.

These solutions are not complicated, and you can easily do it by following the below-given information.

Solution 1:Refresh the webpage

One of the best solutions, when you encounter server error 503, is to refresh your webpage. I have discovered that this solution works for many people. It could actually be the only solution you need. To refresh your webpage, you will have to go through the guide below.

Try the URL from the address bar again by clicking the refresh or reload button. Alternatively, you can just press F5.
Though the 503 error means that there is a problem on another computer, the error may be temporary. You may only need to try the page again to fix it.

If you encountered the error while paying for an online purchase, you should know that several checkout attempts will probably lead to multiple orders. These multiple orders attract multiple charges.  Even though most payment websites have some kind of protective system for this kind of situation, it is crucial to be aware of it.

However, if you could not solve the error after refreshing the web page, you should go down to the next potential solution below.

Solution 2:Reboot your router

Try restarting your modem and router, and then your PC or device, especially if you see the message “Service Unavailable – DNS Failure.” The 503 error is probably the fault of the website you are trying to access.  Probably, there is an issue with the DNS Server configurations on your PC or router, and a restart of both might correct may fix the error.

To reboot your router:

Step 1: Unplug the router or modem from the power source. Do not just turn it off.
Step 2: Wait for about 15 to 20 seconds before plugging it back into the power source.
Step 3: Wait for the device to turn back on.

To reboot your computer:

Step 1: Click on the Windows Start button.

Step 2: Access the small arrow near Shut down and click on Restart to quickly reboot your computer.

If resetting your device failed to rectify the 503 DNS Failure error, the issue may be with the DNS servers themselves. But do not worry because in this case, it is temporary.  However, if you cannot wait for the error to be rectified, pick new DNS servers from any Free and public servers online and change them on your computer or router.

If you were not able to solve the error after rebooting your router, you should go down to the next potential solution below.

Solution 3:Contact the Website

Another option for you if you are looking to fix the 503 error is to contact the website directly and ask for assistance. The administrators of the site probably already know about your situation. But it is still a good idea to let them know. You can send an email to the website explaining the whole situation. 

If you were not able to solve the error after contacting the website, you should go down to the next potential solution below.

Solution 4:Try Again Later

As I mentioned earlier, the error 503 is a temporary server error. It happens regularly on very popular websites when there is a huge increase in traffic by visitors. This increase in traffic overwhelms the servers, leading to the error.

Therefore, sometimes, you can also fix the error 503 by simply waiting for a while before trying again.

Sincerely speaking, this is the solution you are most likely going to use for a 503 error. When more and more visitors exit the website, the probability that you will load the page successfully increases.

What causes Error 503 Backend Fetch Failed

You are likely to encounter the error 503 due to a couple of reasons. But it mainly points to some issues with your server. 

The application pool serves you might have been crashed. 
The server does not have sufficient memory.
There are many requests to the server than it could normally handle.
The SSL cert on the IIS server could be expired. 
The server may be too busy, or there is maintenance being done on it.

Nonetheless, when you see this error on your screen, you need to fix it with the steps I detailed within the next section.

Error 503 Backend Fetch Failed Varnish Cache

If you are on the backend and checking up solutions to error 503, there is a chance that you are a website owner. In this case, you can simply get rid of this error by checking your plugins and restarting your router or modem. To check your plugins following the guide below.

If you face the error 503 on your website, check whether you have the Varnish plugin enabled. The Varnish plugin or the lack of it is one of the main causes of this error. You should know that the Varnish plugin is used for the purpose of increasing the speed of the site. Most hosting firms use it. If you have the plugin enabled on the server, contact the hosting firm, and let them help you.

Sometimes, DNS failure is also on the cards. If this is the scenario, you should be able to get rid of the error by restarting your router or modem. The “service unavailable DNS failure” could be a result of some issues with the DNS arrangement, but restarting it should reset it to normal. To reboot your router, you need to follow the below-given guide:

Step 1: Unplug the router or modem from the power source. Do not just turn it off.
Step 2: Wait for about 15 to 20 seconds before plugging it back into the power source.
Step 3: Wait for the device to turn back on.

After performing all these solutions, you should be able to fix the error 503. These solutions can also be applicable if you are trying to fix the “error 503 maximum threads for service reached” and “error 503 backend is unhealthy”. 

Error 503 Backend Fetch Failed Magneto 2 Bitnami

If you have found out that your Magento installation will show the following code: “Error 503: Service Temporarily Unavailable” when you encounter server issues. You are likely to encounter the issue after you upgraded or set up an extension by using Magento Connect. 

The error happens when you convert your website into maintenance mode by “maintenance.flag” file using the Magento website root directory. In this scenario, you will have to remove “maintenance.flag” to fix this error.

Therefore, you can smoothly get rid of the error message “Error 503: Service Temporarily Unavailable” Magento by following the steps below.

Step 1: Log in to the website host.
Step 2: Use an FTP Client like “FileZilla” or Website Host cPanel “File manager” to gain access to your website Host Server.
Step 3: Go to the Magneto website root directory and search for the file “maintenance.flag.” When you find this file, you need to delete it.
Step 4: Now, refresh the Magento website and check if you have fixed the error.


The error 503 backend failed is one that indicates some faults with your server. It is not a rare occurrence when you are browsing through the internet. Most times, it is just temporary because reloading the webpage gets rid of it.

In this review, I have shown you the solutions for this error, and I believe that you can now fix it.