How to fix Google Chrome’s ERR_SPDY_PROTOCOL_ERROR

err_spdy_protocol_error when accessing websites on Google Chrome

Some users report receiving an unexpected error when browsing web pages on Google Chrome. The Chrome error is mostly shown as  This webpage is not available with Error code: ERR_SPDY_PROTOCOL_ERROR. This error happens without a warning and is not related to the aftermath of a suspicious software installation or such.

The ERR_SPDY_PROTOCOL_ERROR happen as the user browses through popular websites, such as Google sites (Gmail, YouTube, or the Google Search), Facebook, Reddit, Tumblr, etc… If you are receiving this error, this is what you should do to fix it. But before we go there, we should understand what causes it at first place and what you can do to prevent it repeating its self in the future.


Google primarily developed and used the SPDY Protocol for manipulating HTPP traffic, increase the web page loading speed, and improve web security. But later in 2015, due to HTTP 2 issues with vulnerability, Google announced ending support for SPDY Protocol. Google ended supporting SPDY and NPN with the release of Chrome 51, meanwhile, Mozilla Firefox followed the same path by dropping its support for them with Firefox 50.

The research tells us that are two major reasons why ERR_SPDY_PROTOCOL_ERROR strikes Google Chrome users.

  1. An outdated version of the Google Chrome browser
  2. Antivirus and Firewall Blocking

How to fix ERR_SPDY_PROTOCOL_ERROR on Chrome?

As this Chrome error happens mostly with HTTPS-enabled websites and sometimes is caused by an antivirus or a VPN software, this what you can do to fix it.

Reset Google Chrome settings to default

  • Open Google Chrome on your computer device.
  • Click More (the three dots) on the top-right section of the browser.
  • Go to Settings.
  • At the bottom of the page, click on Show Advanced Settings.
  • On the Restore Settings box, click Reset.

Resetting settings on your Chrome browser will revert anything to default and you might lose any customizing modification you applied on the browser. If this did not fix the problem, consider clearing cache and cookies.

Clear Cache and Cookies on Google Chrome

  • Open Chrome on your PC.
  • Click More on your browser toolbar.
  • Click on Show Advanced Settings and point to Clear browsing data under Privacy section.
  • Select the beginning of time from when you want the data to be clear and click on Clear browsing data.

Flush Socks on Google Chrome

Google has its own DNS cache and sockets that rely on more than one Domain Name Server. Resetting DNS sockets may help fix connection errors, such as the ERR_SPDY_PROTOCOL_ERROR. Google comes with a built-in tool that allows you to clear/flush socks on Google Chrome and there two ways you can access it.

  • Copy and paste ‘chrome://net-internals/#events&q=type:SPDY_SESSION%20is:active’ on your Chrome browser.
  • Click on the upside-down arrow on the right side of the toolbar and follow by clicking on Flush Sockets.

Flush Sockets on Google Chrome browser

  • Copy and paste ‘chrome://net-internals/#sockets’ on Chrome.
  • Click Flush sockets pool button.

Flush Socket Pools on Google Chrome browser

Clear Host Cache and DNS Cache on Chrome

Clearing the Host Cache and DNS Cache on your browser may avoid this persistent error from happening again. Here’s how to do it.

  • Open Google Chrome browser.
  • Paste the chrome://net-internals/#dns on your browser.
  • Click on Clear host cache button.

Clear Host Cache on Google Chrome browser

To clear DNS cache settings on your

Run Chrome Cleanup Tool

If none of the above steps worked, running the free Chrome Cleanup Tool will help fix the error if an unwanted extension is responsible for the SPDY Protocol Error.

Update Google Chrome

As every post Chrome 50 version drops support for the SPDY Protocol, upgrading your Google Chrome browser must guarantee a fix of this problem. Although some may recommend downloading the latest Chrome version as a first step, acknowledging that there are reasons why you did not upgrade (or decided to downgrade), I decided to list it as the last step.

Check Avast Antivirus Settings

Avast Antivirus and other Avast-associated products are sometimes blamed for the ERR_SPDY_PROTOCOL_ERROR Chrome error. If the SPDY Protocol Error occurs when you visit a few HTTPS-enabled websites (mostly the most popular sites everyone visits, such as Facebook, Reddit, Google, etc…) you may fix it by excluding those particular sites from Avast Web Shield scanning.

  • Open Avast Antivirus on your computer device.
  • Go to Settings.
  • Click on Active Protection.
  • Go to Customize for Web Shield Protection.
  • Click on Exclusions and list the websites that trigger the error.

If the Chrome’s SPDY Protocol Error occurs on a large number of HTTPS websites and they might be too large for exclusion, consider disabling HTTPS scanning on Avast as a whole.

  • Open Avast Antivirus.
  • Click on Settings.
  • Open Active Protection.
  • Click on Customize for Web Shield.
  • Click on Main Settings.
  • Uncheck the Enable HTTPS scanning feature.
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