How To Resolve the ERR_HTTP2_PROTOCOL_ERROR?

Ever been in the middle of browsing your favourite website, and suddenly Boom! You saw an error in the browser “ERR_HTTP2_PROTOCOL_ERROR” Annoying, right?

The “ERR_HTTP2_PROTOCOL_ERROR” error occurs when there is a problem between your browser and the web server, which uses the HTTP/2 protocol while communicating. In this post, we will guide how to fix this error.

What is HTTP/2 and Its Importance?

To understand this error, we have to know about HTTP/2first. Hypertext transfer protocol (HTTP) is a set of rules that define how the browser and server can communicate. HTTP/2 is the updated version of HTTP/1.1, which has been widely used worldwide for the past 15 years.

Today, people are shifting to HTTP/2 because of its better functionality and features, such as High speed, better security, Multiplexing, and many more.

What is ERR_HTTP2_PROTOCOL_ERROR?

The “ERR_HTTP2_PROTOCOL_ERROR” is a common issue that occurs when a user is trying to access a website and the web server uses the HTTP/2 protocol. This error can appear in browsers like Google Chrome, Microsoft Edge, or Mozilla Firefox. It is due to misconfigurations, browser issues, or even server-side problems.

8 Main Reasons for the ERR_HTTP2_PROTOCOL_ERROR

1. Outdated Software

Outdated or legacy software can cause the “ERR_HTTP2_PROTOCOL_ERROR” error to you. Because they don’t support HTTP/2 and other necessary support for the latest web standards. Due to this, the communication between the web server and your device does not work properly.

2. Corrupted Browser Cache

Caching is a very important thing when you visit any website, it stores data locally (in the browser) of the website that you recently visited. This will help speed up the web page loading. But when the Cache data gets corrupted you will face this error.

3. Browser Extensions

Browser extensions provide additional functionality to the browsers such as modifying web pages, changing web requests and many more. Sometimes these extensions conflict with the browser causing this error.

4. Server Misconfiguration

Sometimes everything is okay on the client side but the error is due to not properly configuring of servers. Today, web requests go through many servers like front-end servers (load balancer) and then it passes this request to the backend server, it’s a kind of multi-tier architecture. Any misconfiguration in these servers can lead to this error.

5. Antivirus and Firewall Interference

Firewalls or antivirus software may block or disrupt the HTTP/2 protocol. Which causes the ERR_HTTP2_PROTOCOL_ERROR error. We have to configure the settings for the  HTTP/2 protocol or use an updated firewall solution that supports this protocol.

6. DNS Issues

Misconfiguration in the Domain Name System (DNS) setting can also cause this error.

7. Corrupt Network Configuration

Misconfiguration in network settings can also cause this error. If the device network setting is not set up properly then it causes that error.

8. Website Coding Errors

If the developer of the website makes some mistake while developing the web application or bugs such as logical errors and others can also cause the “ERR_HTTP2_PROTOCOL_ERROR” error.

13 Methods to Fix the “ERR_HTTP2_PROTOCOL_ERROR” Error

Alright, let’s get into the meat of the matter. Depending on whether the issue is on your browser, system, or server, the fixes will differ.

Here is the list of the top 13 methods to fix this error, all the methods are well-tested and proven:

1. Reload the Page and Restart the Browser

When your internet stops working for a few seconds, it causes the “ERR_HTTP2_PROTOCOL_ERROR” error. To fix it follow these steps:

1. For Windows, type the “Ctrl + F5” button in the browser.
2. If you are a Mac user then “Command + Shift + R “.
3. If you are using any Chromium-based browser like Chrome, Edge, or Brave use this method. Write this “chrome://restart ” on the “Search or enter web address” option of the browser.

2. Use a Different Browser or Use Incognito Mode

When we visit a website, our browser saves some data in it in the form of cache data for speed and better performance. Sometimes this issue occurs at our browser level. To fix this follow these steps:

1. Use the Incognito mode.
2. Use a different Browser.

3.  Clear Browser Cache and Data

Clearing the browser Cache and data is one of the best solutions to this error just follow the given steps.

1. Click the three vertical dots in the upper-right corner of the browser.
2. Go to the “Delete browsing data” option.
3. Select “Cached images and files”
4. Click on the “Delete Data” button.

Alternatively, this method works on Chromium-based browsers.

1. Write “chrome://settings/clearBrowserData” on the “Search or enter web address” option of the browser.
2. Click on the “Delete Data” button.

4. Update your Browser

Outdate web browsers that don’t support or unstable version of a browser can also cause this error. To fix it update your web browser just follow these steps.

1. Click the three vertical dots in the upper-right corner of the browser.
2. Go to Setting.
3. Then go to About.
4. Now, update your browser.

Alternatively, for the Chromium-based browsers.

1. Type “chrome://settings/help” on the “Search or enter web address” browser option.
2. Now, update your browser.

5. Disable or Uninstall Browser Extensions

Browser extension has the power to control webpages, web requests and other things within the browser. Sometimes browser Extension conflict or corrupted browser extension can cause this error.

Follow these steps to fix this error if it occurs due to browser extension.

1. Click on the “three dots” in the top-right corner of the Browser.
2. Click on “Browser Extension” > Click on “Manage Extension”.
3. Now, disable all the extensions that you have installed.

6. Disable the Cache System in the Browser

Disabling the cache temporarily through the Developer Tools option can also fix the “ERR_HTTP2_PROTOCOL_ERROR” error. This method prevents to load of the latest version of a site, bypassing the cache.

For Windows:

1. Open Developer Tools by pressing “Ctrl + Shift + I” or right-clicking on the page and selecting Inspect.
2. Go to the Network tab and check the Disable cache box.
3. Reload the page.

For Mac:

1. Open Developer Tools by pressing “Cmd + Option + I” or right-clicking on the page and selecting Inspect.
2. Navigate to the Network tab and check the Disable cache box.
3. Reload the page.

7. Reset the Browser

Another way to fix this error is, to reset your browser to the Default setting. To reset your browser to the default setting follow these steps:

1. Go to the Browser setting option.
2. Go to Reset settings, and click on Restore settings to their original defaults.
3. Now click on the Reset setting button.

Alternatively,

1. Click on “Search or enter web address” or address bar and copy and paste this “chrome://settings/resetProfileSettings?origin=userclick&search=reset” and hit the Enter button.
2. Click on the Reset Setting button.

8. Reinstall the Browser

If you continue to face the ERR_HTTP2_PROTOCOL_ERROR, reinstalling the browser may help resolve the issue.

For Windows:

Open Settings “Press Win + I”.

1. Go to Apps > Installed apps (or Apps & features in older versions).
2. Find your browser (e.g., Chrome, Edge, Firefox), click on it, and select Uninstall.
3. Follow the prompts to remove the browser completely.
4. Download the latest version from the official website and install it.

For Mac:

1. Open Finder and go to the Applications folder.
2. Locate your browser (e.g., Safari, Chrome, Firefox).
3. Drag the browser to the Trash or right-click and select Move to Trash.
4. Empty the Trash to remove it completely.
5. Download the latest version from the official website and reinstall it.

9. Turn Off the Browser’s QUIC Protocol

Quick UDP Internet Connections (QUIC) is a network protocol that supports encrypted data transfer on UDP, it was developed by Google. Its goal was to increase the speed, security, and efficiency of HTTP traffic.

If it is not configured properly on the server side it causes the “ERR_HTTP2_PROTOCOL_ERROR” error. Follow these steps to fix it.

1. Enter this on Chromium-based browsers URL field “chrome://flags/#enable-quic” and hit the Enter button.
2. This option shows on the browser when you hit Enter “Experimental QUIC protocol”
3. Under the “Experimental QUIC protocol”, it is selected to default change it “Disable” option.

Device and Network Solutions

We have seen the list of ways to fix the “ERR_HTTP2_PROTOCOL_ERROR” error at the browser level. But sometimes it occurs due to system and network settings. Let’s see all of them one by one.

10. Check the Device Date and Time

Sometimes wrong Date and time on the device or operating system can cause this error. Because of this very small issue, you are facing it in your browser. When you visit a website, your device and the web server exchange data with timestamps. If your device’s clock is incorrect, the server may see the mismatch as a security risk and block the connection.

Follow these steps to fix the error:

For Windows:

1. Right-click on the clock in the bottom-right corner of your screen and select Adjust date/time.
2. If Set time automatically is turned on but shows the wrong time, switch it off.
3. Make sure the Time zone setting matches your current location.
4. Click Change under Set the date and time manually, then adjust the date and time in the pop-up window.

For Mac:

1. Click the Apple menu > System Settings (System Preferences in older macOS).
2. Go to General > Date & Time.
3. Set time automatically on. If incorrect, turn it off and back on.
4. Ensure the Time Zone is correct or enable the Set time zone automatically.
5. If needed, click Set manually to adjust the date and time.

11. Update Your Operating System

Whether you are a Windows user or a Mac, if your operating system is outdated or you have not updated your Operating System regularly, it will also cause the ERR_HTTP2_PROTOCOL_ERROR error. It is due to your Operating System is not compatible with latest technology.

Follow these steps to fix the error:

For Windows:

1. Click on the Start menu and go to Settings > Update & Security > Windows Update.
2. Click on Check for updates, if an update is available update it.

For Mac:

1. Click the Apple menu (in the top-left corner).
2. Select System Settings.
3. Go to General > Software Update.
4. If an update is available, click Update Now.

12. Reset the DNS setting

Network problems, such as DNS or IP conflicts, can cause the ERR_CACHE_MISS error. Resetting your network settings may help fix these connectivity issues. Follow the below step one by to fix the error.

For Windows:

1. Press the Windows Button.
2. Type CMD.
3. Click on Run as administrator > a prompt appears then click Yes.
4. Type the following command in CMD “ipconfig /flushdns” (without “ ”).

For Mac:

1. Press “Command + Space“ Button.
2. Type Terminal
3. Open the Terminal
4. Type the following command and hit the Enter button “sudo killall -HUP mDNSResponder” (without “ ”).

13. Check Antivirus Software

Sometimes this error occurs due to the Antivirus software installed on the Operating System (OS). Follow these steps to fix the error.

1. Check if there is any update of your antivirus software is available. If an update is available update it.
2. Disable your antivirus software temporarily.

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