On a computer running the Windows operating system, there are situations when the user is unable to access the site due to the “ERR HTTP2 PROTOCOL ERROR” error. This error appears on different browsers: Google Chrome, Yandex Browser, Mozilla Firefox, Opera, Microsoft Edge, Vivaldi, Brave and other Internet browsers.

Currently, most websites use the HTTP/2 network protocol, which ensures fast transfer of virtual data. This protocol is used by web browsers, applications and content management systems.

n most cases, the “ERR_HTTP2_PROTOCOL_ERROR” error appears due to problems with the browser, network, or conflicts with third-party software. If an HTTP/2 protocol error occurs, the connection between HTTP and the user’s device is interrupted.

The most common causes of the error:

  • Outdated software – The operating system or web browser on your computer is outdated and may not be compatible with a particular site.
  • Browser Cache Corruption – This prevents your device from being authenticated, causing the web server to not establish a connection and returning this error. For example, you will see the message “An error occurred while establishing a secure connection.”
  • Conflict between browser extensions – this causes communication with the website server to be interrupted.
  • Impact of an antivirus or firewall – security systems block access to certain sites.

How to fix ERR_HTTP2_PROTOCOL_ERROR error in browser

Once you receive the “ERR_HTTP2_PROTOCOL_ERROR” error, you can begin troubleshooting to find the source of the problem.

Use the suggested methods to fix the situation in the browser:

  • First, try refreshing the inaccessible web page by pressing “F5”. This may solve the problem if the site is temporarily unavailable.
  • Open the problematic page using a different browser, as it is possible that a specific web browser on your PC is crashing.
  • Update your browser. Using an outdated browser may result in an HTTP/2 protocol error because your browser’s data packets are not compatible with the site.
  • Clear cache and cookies in your browser. Clearing your cache, cookies, and history will help websites you visit re-authenticate your device and complete your request.
  • Open your browser in incognito mode. When running the browser in private mode, cache and cookies are not used and extensions are disabled. Thanks to this, their negative influence is eliminated. As a one-time solution, you can use this method to open the problematic page.
  • Disable or remove browser extensions to see if the error goes away. Third-party extensions can potentially interfere with the interaction between your browser and the web page.
  • Disable the QUIC protocol in your browser. Quick UDP Internet Connections (QUIC) is an encrypted transport network protocol developed by Google to improve the speed, security, and efficiency of HTTP traffic.

To resolve this issue due to possible protocol errors, disable QUIC in your browser.
 – In the Google Chrome browser window, enter the following URL in the address bar:


 – On the page that opens, you will see a highlighted result labeled “Experimental QUIC protocol.”
 – Change the setting to “Disabled”.

  • Reset browser settings to default. This method allows you to return the browser to its normal state with the original values. The error may go away if it is caused by incorrect browser settings.

Keep in mind that resetting your browser will delete your current search history, temporary site data, cookies, disable extensions, and change other program settings.

Go through the steps:

 – Open Google Chrome settings.
 – On the left, open the “Reset Settings” tab.
 – Then select the Restore Defaults option.”
 – In the “Reset settings?” pop-up window. Click on the “Reset settings” button.

We have looked at some ways to fix the “ERR_HTTP2_PROTOCOL_ERROR” error using a web browser. But, not in all cases the browser is the source of the problem.

Setting the correct date and time on your computer

Your computer should display the correct date and time. If this information is inaccurate, data packets with incorrect timestamps may be rejected. This causes the error “ERR_HTTP2_PROTOCOL_ERROR” to appear.

Reset DNS cache

DNS is the Internet’s Domain Name System for obtaining information about all available websites and their unique IP addresses. After visiting a site, the browser or operating system stores this information in a database. This is necessary to speed up the loading of websites you visit again.

If you receive the “ERR_HTTP2_PROTOCOL_ERROR” error, try clearing your DNS cache to erase IP addresses and other data from your computer.

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