Are you looking for answers to the error message “Error 503 Backend Fetch Failed” and ways to fix it? Well, you’ve landed in the right spot.
Generally, when the HTTP cache cannot retrieve the requested data from the web server, an alert message saying “Error 503 Backend Fetch Failed” will be displayed. This can happen due to various reasons such as server overloads, maintenance, or other technical issues.
In this post, we will cover every aspect related to “Error 503 Backend Fetch Failed,” including what it means, what causes it, and how you can fix it in a comprehensive manner. So, stay tuned and keep reading this article until the end.
Let’s get started!
What is Error 503 backend fetch failed?
The Error 503 backend fetch failed is an HTTPstatus code that simply indicates that the website you’re trying to visit is temporarily unavailable or experiencing problems on the server side. You may need to wait a while and try again later, or contact the website administrator for more information.
The error can be displayed or triggered for any device, no matter your operating system or browser.
Sometimes, the server that hosts a website starts acting up and not doing its job properly. This error happens when the website’s server is overburdened with too many requests and unable to process them.
Imagine you’re going to a busy store, and lots of people are asking for help at once. If the store staff can’t keep up, things get messy.
When you visit a website that takes too long to load, lots of requests can pile up. If the website’s server can’t handle all these requests, it gets overwhelmed.
Also, the memory in your web browser might get filled up, which can cause an error linked to a problem with fetching information from the server’s backend.
You might encounter the ‘Error 503 Backend Fetch Failed’ if your internet connection is unstable or slow. When you attempt to visit a website and it takes a longer time to load because of a sluggish connection, requests start piling up.
Consequently, the website’s data collects in a storage space called a cache. However, when this storage becomes too full, it leads to an issue and displays the ‘Backend Fetch Failed’ error.
2. Server Temporarily Down
Ongoing server maintenance for example during a plugin, theme, or software update can possibly cause this HTTP error 503. In this case, the server goes into ‘maintenance mode’ and will display a message on your browser, “Error 503 backend fetch failed” You can also check if your site is down for others too.
3. Issue with Plugins or Website
If the website you are visiting is hosted on a shared server, and any of the plugins or websites hosted on that same server are faulty, it can also cause this error for other sites hosted on the same server.
4. Heavy Packet loss
Heavy packet loss is when data traveling across a network, like the Internet, is experiencing significant disruption or loss. When you send information online, it’s split into small units called “packets.” These packets move from one place to another to create websites, videos, messages, and more.
When there’s heavy packet loss, some of these packets don’t reach their destination. This can cause problems in things like video calls or slow down website loading. It usually happens when the network is crowded, unstable, or facing technical issues.
5. Website blocked
When you try to open a website that has a bunch of ads, and you’re using a tool such as Adblocker, this tool stops the ads from showing up.
Because of this, the website’s content doesn’t load properly. This can make a bunch of requests pile up, leading to the error we’re talking about. Also, your browser has other safety things that can stop shady websites from loading, and that’s another reason you’re seeing this error right now.
How to fix “Error 503 backend fetch failed”?
Since the ‘Error 503 Backend Fetch Failed’ error is a server-side issue, there isn’t much you can do from your side. However, that doesn’t mean you shouldn’t at least give it a try. There are some troubleshooting methods you can follow to ensure everything runs smoothly from your end.
The ‘Error 503 Backend Fetch Failed’ error is a server-side issue and can occur due to temporary server maintenance. Therefore, simply refreshing or reloading the webpage a few times might solve the problem.
However, if that doesn’t work, we have other methods available to fix it, which are explained below.
2. Close other multiple active Tabs
Sometimes, the ‘Error 503 Backend Fetch Failed’ can also be triggered due to having multiple active tabs open, which can overwhelm the caching server. Therefore, to alleviate the strain on the caching server, it is advisable to close any other active tabs when encountering such error messages on your current tab.
3. Check if there is too much packet loss
As we have already mentioned earlier that heavy packet loss can also be one of the reasons that trigger the ‘Error 503 Backend Fetch Failed’ error. To check this, you need to run a ping test, Here is how you can do it.
A ping is a tool used to measure the time it takes for data to travel from your computer to another computer (host) and receive a response back (ACK handshake). To make sure the test is accurate, it’s a good idea to use a larger packet of data (10000 bytes) than the default size. Here’s how you can do it:
For Windows users:
Press the Windows key + R to open the Run dialog box.
Type “cmd” and press Enter to open the Command Prompt.
Type “ipconfig” and press Enter to display information about your network adapter.
Make a note of the “Default Gateway” value. You’ll need this for the next step.
Type “ping Default Gateway -t -l 10000” and press Enter.
After about 15 pings, press Control + C to stop the ping test.
For Mac users:
Open the Terminal.
Type “ipconfig” and press Enter to display information about your network adapter.
Make a note of the “Default Gateway” value. You’ll need this for the next step.
Type “ping Default Gateway -s 10000” and press Enter.
After about 15 pings, press Control + C to stop the ping test.
If you find that there is heavy packet loss, you can either move nearby to your wifi router or use the fastest internet connection such as Ethernet.
4. Restart your Device and Router
Sometimes, the error may be caused by temporary glitches or conflicts on your device. Restarting it can clear out any issues. On a computer or smartphone, save your work and close any open applications.
Choose the restart option from the power menu or simply turn off your device and then turn it back on. Once your device restarts, try accessing the website again to see if the error is resolved.
Also, Network problems can trigger the “Error 503” message. Restarting your router can refresh the connection and potentially resolve the issue. Here’s what to do:
1. Locate your router and find the power source.
2. Unplug the power cable from the router and wait for about 10-15 seconds.
3. Plug the power cable back in and wait for the router’s lights to stabilize.
4. Once the router has fully restarted, attempt to access the website again to check if the error is gone.
5. Reset your Current Browser to default settings or alternately use a different browser
Sometimes, if your web browser isn’t set up properly, you might see these errors. The easiest way to fix this is to reset your browser back to its default settings.
To reset Chrome settings to their default and see if it resolves the issue.
5.1. Open the Chrome browser.
Reset Chrome Settings
5.2. Click on the three-dot menu button at the top-right corner.
5.3. From the menu, select “Settings.”
5.4. On the left side of the page, find and click on “Reset and clean up.”
5.5. Now, on the right side of the page, click on “Restore settings to their original defaults.”
Chrome Restore Settings
A confirmation pop-up will appear. Click on “Reset settings” to continue.
Chrome Reset Settings
Follow any further instructions that come up to finish the process.
Once everything is done, restart Chrome.
OR
you can try a different browser such as Mozilla Firefox or Edge alternatively.
6. Examine Varnish Plugin
If your website is using a Varnish Cache, the first thing you need to do is to find out whether the error occurred due to the Varnish plugin or the Web server.
To figure it out, the best thing you can do is to disable the Varnish and try to fetch without it. After that, see if the “Error 503 backend fetch failed” still exists. If no then, your Varnish Plugin is the main culprit.
To do so,
1. Open your cPAnel and login it with your credentials.
2. Go to the Web Accelerator section > Choose to Manage Varnish > Click on”Disable Varnish” as shown below.
Disable Varnish
3. Now click on “Confirm Action” to Disable it.
You’ve successfully managed to turn off or disable Varnish for your website. Now, try loading your website to see if the error is fixed. If it is, that suggests something might have gone wrong with your Varnish plugin.
You can turn it back on to see if restarting the Varnish plugin resolves the issue or not.
If the error still doesn’t go away, you’ll need to conduct a more thorough investigation by reviewing the error logs, which will help you to determine a clear picture.
To generate a log file follow the steps given below:
Follow these commands to log entries where the varnish response or backend response status is 503.
$ varnishlog -q 'RespStatus == 503' -g request
To log all entries >=500, use the following command,
varnishlog -a -w /var/log/varnish/varnish50x.log -q “RespStatus >= 500 or BerespStatus >= 500”
7. Increase the cache Tag Length
By default, Varnish has a cache tag length of 8192 bytes. If this length exceeds due to some reason, the Error 503 backend fetch failed will occur.
To resolve this, you can increase the value of your Varnish cache tags. To do this, simply raise the value of the parameter “http_resp_hdr_len” in your Varnish configuration file.
DAEMON_OPTS is used by the init script. DAEMON_OPTS="-a ${VARNISH_LISTEN_ADDRESS}:${VARNISH_LISTEN_PORT} \ -f ${VARNISH_VCL_CONF} \ -T ${VARNISH_ADMIN_LISTEN_ADDRESS}:${VARNISH_ADMIN_LISTEN_PORT} \ -p thread_pool_min=${VARNISH_MIN_THREADS} \ -p thread_pool_max=${VARNISH_MAX_THREADS} \ -p http_resp_hdr_len=70000 \ -p http_resp_size=100000 \ -p workspace_backend=98304 \ -S ${VARNISH_SECRET_FILE} \ -s ${VARNISH_STORAGE}"
8. Try making changes to Varnish and NGINX config files
The steps provided are applicable to both Varnish and NGINX. Here’s how you can adjust the configuration:
For Varnish:
Locate and open the file located at /etc/varnish/default.vcl .
Look for the line that reads .url = “/pub/health_check.php”; and modify it by removing /pub,
like this:
Original: .url = “/pub/health_check.php”;
Modified: .url = “/health_check.php”;
Modifying Varnish and NGINX Files
Alternatively, if there’s no /pub, consider adding it if needed.
The next thing you need to do is to, Go to the Magento 2 main folder and open the file named nginx.conf.sample.
Find this line: location ~ (index|get|static|report|404|503).php$ {
Edit the line by adding “health_check” to it, like so:
After making these changes, save the file and restart Varnish.
9. Contact Your Web host or Website admin
If none of the above-mentioned troubleshooting methods work to fix the “Error 503 backend fetch failed” error. The last option left you to contact your web hosting provider and ask them for support. OR you can contact the website admin and intimate them about the issue.
Conclusion
In the above post, we tried to cover all about the “Error 503 backend fetch failed” problem and gave you 9 effective troubleshooting methods to fix it.
If you notice anything we missed or have any questions about what we talked about, please tell us in the comments below. We’d love to hear from you!
Frequently Asked Questions
How do I fix 503 backend fetch failure?
Here are some of the troubleshooting steps you can try to fix Error 503 backend fetch failed: 1. Refresh or Reload the Webpage 2. Close other multiple active Tabs 3. Check if there is too much packet loss 4. Restart your Device and Router 5. Reset your Current Browser to default settings or alternately use a different browser 6. Examine Varnish Plugin 7. Increase the cache Tag Length 8. Try making changes to Varnish and NGINX config files 9. Contact Your Web host or Website admin
What is a 503 backend error?
The Error 503 backend fetch failed is an HTTP status code that simply indicates that the website you’re trying to visit is temporarily unavailable or experiencing problems on the server side. You may need to wait a while and try again later, or contact the website administrator for more information.
How do I fix error 503 on my Android?
To fix error 503 on your Android device, you can try the following steps: 1. Restart your device 2. Check your internet connection 3. Clear app cache and data 4. Update the app 5. Uninstall and reinstall the app
