How To Fix ERR_HTTP2_PROTOCOL_ERROR

In today’s digital world, websites need to be fast and efficient. HTTP/2 is the latest version of the HTTP protocol that helps websites load quicker by improving how data is sent and received. However, like any technology, it can sometimes run into issues.

One common problem is the ERR_HTTP2_PROTOCOL_ERROR. The http2 protocol error can disrupt the smooth functioning of your website, making it inaccessible to visitors. So, you must resolve this error to ensure your site remains user-friendly and reliable.

In this tutorial, we’ll guide you through the basics of HTTP/2, explain what causes the NET::ERR_HTTP2_PROTOCOL_ERROR, and provide simple steps to fix it on your web browser and devices. Whether you’re a beginner or have some technical knowledge, these methods will help you troubleshoot the error and get your website back on track.

KEY TAKEAWAYS

1. Refresh the web page to see if the error is temporary.
2. Make sure your browser and operating system are updated.
3. Clear your browser’s cache, cookies, and history.
4. Disable or uninstall browser extensions that might be causing conflicts.
5. Turn off the browser’s QUIC protocol if required.
6. Restore your web browser to its default (original) settings to remove any problematic configurations.
7. Check and adjust your device’s date and time settings.
8. Flush the DNS to clear outdated records.
9. Review antivirus software settings that might be blocking connections.

What Is ERR_HTTP2_PROTOCOL_ERROR?

The ERR_HTTP2_PROTOCOL_ERROR is an error message that occurs in web browsers when there is a problem with the HTTP/2 protocol during the communication between the browser and the server.

Here, HTTP/2 is an advanced version of the HTTP protocol, which is created to enhance the performance of web interactions by enabling numerous requests and responses to be sent simultaneously over a single connection. To simplify it and help you understand, here’s an example.

Imagine you’re playing a game with your best friend, and you both have agreed on a set of rules for how to play. Now, if one of you breaks these rules, the game stops, and you can’t continue until you fix the problem. This is basically what’s happening with the ERR_HTTP2_PROTOCOL_ERROR.

When you access a website, your browser and the website hosting server must communicate using a specific set of rules called HTTP/2. HTTP/2 is like a new and improved set of rules that helps the computers and websites talk faster and more efficiently.

These rules help your browser quickly load web pages by allowing multiple pieces of information to be sent simultaneously. It’s like playing a game where you can make several moves at once, which makes the game go faster.

However, sometimes, your browser or the server could break these rules. When this happens, they can’t understand each other properly, and the connection is interrupted.

This is when you see the ERR_HTTP2_PROTOCOL_ERROR message. It means something got mixed up while your browser and server were talking to each other, and they need to fix it before you can view the website. This mix-up can happen for several reasons, like bad connections, broken rules, and website issues.

The representation of the ERR_HTTP2_PROTOCOL_ERROR may differ based on what browser you’re using. However, Google Chrome displays the ERR_HTTP2_PROTOCOL_ERROR error code with a message that tells you the site can’t be reached because the “web page at [domain.com] might be temporarily down”. Or, it may have permanently moved to a new web address.

Today, most browsers, applications, and systems use the HTTP/2 network protocol, which offers enhanced efficiency for digital communication. Despite the advantages of this updated protocol, you might still encounter errors while trying to access online content.

Sometimes, the ERR_HTTP2_PROTOCOL_ERROR can appear as an HTTP error message, blocking access to the online resource you’re trying to reach.

Causes of ERR_HTTP2_PROTOCOL_ERROR

There are several factors that can trigger the NET::ERR_HTTP2_PROTOCOL_ERROR. Here are the most common ones:

1. Outdated Software: Using an old version of your browser or server software can lead to compatibility issues with HTTP/2.
2. Corrupted Browser Cache: Over time, your browser’s cache can get corrupted, causing errors like this.
3. Conflicting Browser Extensions: Some extensions can interfere with how HTTP/2 works, leading to problems.
4. Server Configuration Problems: Misconfigured servers might not handle HTTP/2 requests properly.
5. Website Coding Errors: Bugs in the website’s code can disrupt the protocol.
6. Third-Party Antivirus or Firewall Interference: Security software might block or interfere with HTTP/2 connections.

Now that you understand the http2 protocol error and what can initiate it, let’s explore some solutions. First, we’ll see how to fix this error on the browser. Then, we’ll show you how to resolve it on a device.

How to Fix ERR_HTTP2_PROTOCOL_ERROR in A Browser

Let’s start with the easy methods and move on to the more detailed ones.

Refresh Web Page

Sometimes, the error happens because of a temporary problem, like a momentary loss of connection or a small hiccup in the data you send. Therefore, the first and simplest step to try when you see the ERR_HTTP2_PROTOCOL_ERROR is to refresh the page.

To refresh, simply click the refresh button in your browser’s toolbar or press F5 on your keyboard.

Now, you might be wondering how refreshing a web page can fix the HTTP2 protocol error. Refreshing forces the browser to reload the page and establish a new connection with the server.

When you refresh, your browser discards the current connection and any temporary data stored, like cached files or session data, and attempts to retrieve the page from the server again.

This can help settle any temporary issues that may have occurred during the initial connection, such as incomplete data transmission or minor network glitches.

Another reason refreshing might help is that it can clear up minor errors that occur during the initial loading of the page. Additionally, refreshing the page might help if the error was due to a momentary conflict or an issue with the browser.

Alternatively, you can try a different web browser or device, or try the private mode of your browser. However, if the error persists after you refresh or test on a different browser, it might indicate a deeper issue that requires further troubleshooting. Usually, a quick refresh fixes the problem and returns you to smooth browsing.

Update Your Browser

If you use an outdated browser, this can often cause errors like ERR_HTTP2_PROTOCOL_ERROR. That’s because the browser may not support the latest protocols and features. To fix this, make sure your browser is updated. Most modern web browsers update automatically, but you can also check manually whether this has been done. Let’s see how to do it in Chrome, Edge, and Firefox.

Google Chrome

Click the three dots in the top right corner, go to Help, and then About Google Chrome.

If an update is available, it will start automatically.

Microsoft Edge

Go to ⋯ → Help and feedback → About Microsoft Edge. This will also update automatically.

Mozilla Firefox

Go to ≡ → Help → About Firefox.

We recommend you keep your browser updated to ensure compatibility with the latest web technologies and security standards. Once your browser is updated, return to your web page to see if the error has been resolved. If so, enjoy browsing; otherwise, there may be issues with your browser’s cache.

Clear Your Browser Data

If you encounter errors during the rendering process, it’s a good idea to clear your web browser data. By flushing your cache, history, and cookies, you can enable visited sites to authenticate your device and fulfill the request.

Before continuing with the steps to clear data, let’s understand how browser data can cause an http2 protocol error and why it is important to clear it.

Imagine your browser cache is a backpack that stores copies of websites that have been visited previously. This helps your browser load those websites faster the next time you visit, as it doesn’t have to download everything from scratch.

But sometimes, the backpack can get filled with old or incorrect copies of the website’s files. If the website has been updated since you last visited, but your browser still uses the old files from the backpack, it might not match what the website’s server expects.

This mismatch can be confusing; like trying to assemble a puzzle using pieces that don’t fit. When this happens, your browser and the website can’t communicate properly. This would lead to the NET::ERR_HTTP2_PROTOCOL_ERROR.

It’s like if you use an old map to find a new location — this doesn’t work well! Clearing the cache or emptying the backpack can help fix this problem by forcing the browser to get the latest, correct version of the website’s files from the server. This can help everything work smoothly again, without errors.

Google Chrome

To clear browser data in Chrome, go to ⋮ → Delete browsing data. The Delete browsing data window will pop up and you should switch to the Basic tab. Then, select a time range (e.g., Last hour, Last 4 weeks, or All time). Next, checkmark the following checkboxes and click Delete data:

• Browsing history
• Cookies and other site data
• Cached images and files

Microsoft Edge

Open the Edge browser on your computer. Click on ⋯ and select Settings from the dropdown menu. Click on the Privacy, search, and services option in the Settings menu.

Alternatively, you can type edge://settings/privacy URL in the browser’s search box. Then, scroll down to the Delete browsing data section and click Choose what to clear.

edge://settings/privacy

In the Delete browsing data window, use the Time range dropdown to select how far back you want to clear data (e.g., Last hour or All time). You’ll also see a list of data types, such as browsing history, cookies, and cached images and files. Check the boxes next to the data types you want to clear. For a thorough cleaning, you can select the following options:

• Browsing history
• Cookies and other site data
• Cached images and files

After selecting the data types and time range, click on the Clear now button.

Mozilla Firefox

Open Firefox browser and go to ≡ → Settings → Privacy & Security. Page down to the Cookies and Site Data section. Then, Click on the Clear Data… button.

A window will pop up where you must tick the checkboxes labeled History, Cookies and site data, and Temporary cached files and pages. Finally, click on the Clear button to delete the selected data.

Important: Clearing your browser data can help resolve issues like slow browsing, errors, or outdated content. However, this process will log you out of websites and remove stored information such as site cookies and preferences.

Disable Or Uninstall Browser Extensions

If clearing browser data doesn’t fix the http2 protocol error, you may be using a third-party browser extension that is causing this error. To troubleshoot this, try disabling your Chrome extensions.

To do this, ⋮ → Extensions → Manage Extensions. Now, toggle off the Chrome extensions one at a time to identify any causing issues.

Edge users can use edge://extensions/ and Firefox users can type about:addons in their browser’s search bar and hit Enter. This will take you to the page where you can disable or uninstall faulty extensions.

about:addons 

If the error disappears after disabling a particular extension, consider uninstalling it or finding an alternative. This process helps ensure that no unnecessary extensions are causing conflicts with your browsing experience.

Turn Off The Browser’s QUIC Protocol

Quick UDP Internet Connections (QUIC) is a network protocol created by Google that enhances the speed, security, and efficiency of HTTP traffic because it provides an encrypted method of transport.

QUIC combines the benefits of HTTP/2, such as multiplexing (sending multiple streams of data over a single connection), with additional improvements in latency, connection establishment, and congestion control (a mechanism that controls data packets’ entry into the network).

Statistics tell us that 8.1% of websites use QUIC. When a website isn’t set up to handle this type of traffic, it can lead to incompatibility issues between the client and server. This can sometimes result in an http2 protocol error. In this case, you need to disable the QUIC protocol in your Chrome browser.

However, before you continue the disabling process, we recommend checking the web page to see if it supports the QUIC protocol. To do so, go to your desired web page and press Ctrl + Shift + I to open developer tools. Click on the Network tab. Then, press Ctrl + R to reload the page.

Once the page is fully loaded, see if the Protocol column contains the h3 value. QUIC is often associated with HTTP/3, so seeing h3 in the Protocol column usually indicates that the QUIC protocol is being used.

Important: If the Protocol column is not visible, you may need to right-click on the header row in the Network tab and select Protocol to display it.

If the web page you’re trying to access uses QUIC protocol, you don’t need to disable it from your browser because it’s not the root cause of the error. However, if the site doesn’t support QUIC, you should disable it from your Chrome browser.

To do this, type chrome://flags/ in your Chrome browser address box (a.k.a. address bar) and hit Enter. Search for QUIC and set the Experimental QUIC Protocol to Disabled. You will be prompted to restart your browser; to do this, click Relaunch.

chrome://flags/

This should help if the QUIC protocol was the cause of the problem. Remember to re-enable this if necessary, as QUIC generally improves browsing speed and security.

Restore Browser’s Default Settings

When you use a browser, you may not notice the small glitches that can modify your browser’s default settings; these ultimately lead to NET::ERR_HTTP2_PROTOCOL_ERROR. However, you don’t need to worry because there’s a simple way to restore your Chrome browser to default settings. Here’s how:

Go to ⋮ → Settings → Reset settings and click on Restore settings to their original defaults.

Lastly, confirm that you want to erase Chrome settings by clicking Reset settings.

It’s also important to note that resetting Chrome settings to the original will disable extensions, delete cookies and other temporary site data, and reset some Chrome settings and Chrome shortcuts. However, your current search history, bookmarks, and saved passwords will not be affected.

As you’re resetting the settings, you may also want to reset the experimental settings in your Chrome browser. As they aren’t fully functional and tested features, they can also prevent you from accessing the web page.  To do this, type the following link in your Chrome:

chrome://flags/

Click Reset all in the upper-right corner. This will restore the default settings for features that were accidentally enabled.

Don’t forget to relaunch your browser because these changes will only take effect after relaunching the browser. Now, go back to your site and see if the ERR_HTTP2_PROTOCOL_ERROR persists.

Reinstall Google Chrome

If you’ve tried all these methods and are still encountering the persistent ERR_HTTP2_PROTOCOL_ERROR error, there might be an issue with the Google Chrome app. Even if you’ve restored the default settings, it could help if you reinstall the browser.

To start, you’ll need to uninstall the browser from your device. To do this, navigate to Control Panel → Programs → Programs and Features. Then, right-click on the Google Chrome application and select Uninstall/Change.

Now, download the latest Chrome browser from Google Chrome’s official website. Once the download is complete, double-click on it and follow the on-screen instructions to install. Now, you should be able to access your desired website without an issue.

How To Fix ERR_HTTP2_PROTOCOL_ERROR On A Device

Previously, we’ve learned various methods to fix the NET::ERR_HTTP2_PROTOCOL_ERROR error when using a web browser. However, in some cases, browsers do not originate the http2 protocol error. Here, you need to resolve it on your device. Let’s explore various approaches that you can use to make your device compatible with the HTTP2 protocol.

Reset Device’s Date & Time

This may not seem like a major issue, however, any incorrect date and time settings on your machine could cause the ERR_HTTP2_PROTOCOL_ERROR. Websites use these settings to verify SSL certificates and ensure secure connections. Here’s how to fix it on Windows:

Go to Start menu → Settings → Time & Language → Date & Time. Toggle on Set time automatically and choose the correct value for Time zone.

If you don’t want it done automatically, click on Change to set the date and time manually.

After making these changes, try revisiting your web page. This simple adjustment can resolve the error by ensuring your device’s time matches the web server, allowing secure connections.

If you are still having issues, try clicking Sync now;this will synchronize your time with the server.

Update Your Operating System

Keeping your device’s operating system updated is crucial for maintaining compatibility with the latest internet protocols, including HTTP/2. An outdated OS can cause errors like ERR_HTTP2_PROTOCOL_ERROR due to missing updates or security patches. Here’s how to update your OS on Windows:

Go to Start menu → Settings → Update & Security → Windows Update. After that, click Check for updates and install any available updates.

Windows will now search for available updates. If there are any updates available, they will be downloaded and installed automatically. You may need to restart your computer to complete the installation.

Flush The DNS Cache

Before we flush the Domain Name Systems (DNS) cache, let’s understand it first. Imagine you own a notebook where you write down your friends’ phone numbers. This notebook helps you call your friends quickly because you don’t have to remember their numbers or look them up every time.

Now, think of the DNS cache as your computer’s notebook that stores the website addresses you’ve visited. This helps your computer find and load websites faster.

Sometimes, though, the numbers in your notebook might be wrong or outdated, and when you try to call friends, you can’t reach them. Similarly, if the DNS cache on your computer has old or incorrect information, it can cause problems when you try to visit a website.

One of these problems might be an ERR_HTTP2_PROTOCOL_ERROR, which means your computer can’t connect to the website correctly because it’s using the wrong address.

To fix it, you need to flush the DNS cache; this is like erasing the old numbers in your notebook and filling in the correct ones. Flushing the DNS cache removes all the old or incorrect addresses so your computer can find and connect to the websites properly using the latest information.

This can help solve the ERR_HTTP2_PROTOCOL_ERROR and ensure your computer calls the right number for the website you want to visit.

To flush or remove the DNS cache, press the Win + R hotkey combination to open the Run window, write cmd, and press OK (you can also press Enter).

You’ll get Command Prompt opened, type ipconfig /flushdns, and press Enter.

ipconfig /flushdns,

You should see a message saying, “Successfully flushed the DNS Resolver Cache”. Now, try to revisit your website to see if the error is resolved.

Check Antivirus Software

Most of the time, people install antivirus software to keep their devices safe while browsing. You may also have done this. It’s a good idea to check if the antivirus you installed may be causing the error.

Start by checking your notifications, which may show new security alerts. Many antivirus programs also have a quarantine section that lists all the detected security threats on your computer. Look through these areas to see if any unwanted applications are being identified. If you find any, you might need to disable your antivirus software temporarily.

After disabling it, go back to the web page showing you the ERR_HTTP2_PROTOCOL_ERROR error, and refresh it. You should be able to access the site now. If you can access the site, find alternate antivirus software for your device and install it to keep it safe and secure.

FAQs

Other Related Tutorials & Blogs:

– How To Fix ERR-CONNECTION_CLOSED in Google Chrome

– How To Fix ERR_NAME_NOT_RESOLVED Error

– How to Fix ERR_CONNECTION_TIMED_OUT Error

– How to Fix ERR_TOO_MANY_REDIRECTS Error

– How to Fix: This Site Can’t Provide a Secure Connection Error