Google Chrome claimed the throne of the most widely used browser in the world and has managed to keep it for close to a decade now. Having such a massive user base also means that quite a lot of errors could crop up unexpectedly. One such issue is the 'ERR_SPDY_PROTOCOL_ERROR.' It is related to the deprecated SPDY ('speedy') open-specification networking protocol that was developed to transport Web content more efficiently. As part of Google Chrome, the protocol manages HTTP traffic to reduce Web page load times and latency as well as boost web security. As for the 'ERR_SPDY_PROTOCOL_ERROR,' there are numerous reasons that could explain its appearance. High network latency, using an older Chrome version, interference from an anti-malware security solution could all lead to the error. If updating Chrome or stopping your security product doesn't seem to affect the 'ERR_SPDY_PROTOCOL_ERROR,' try the solutions outlined below and see if they are able to help.

Flush Sockets in Chrome

  1. Open Chrome. 
  2. Paste or type chrome://net-internals/#events&q=type:SPDY_SESSION%20is:active into the address bar and press Enter on your keyboard.
  3. Click on the arrow located in the top-right corner.
  4. From the available options in the drop-down menu, select 'Flush sockets.'
  5. See if the page now opens normally.
  6. If the 'ERR_SPDY_PROTOCOL_ERROR' is still there, paste chrome://net-internals/#sockets into the address bar and press Enter.
  7. Choose 'Flush socket pools.'

Flush the DNS via Command Prompt

Another potential solution for the problem is to flush the DNS (Domain Name System). One of the fastest methods to do so is via the Command Prompt. Type command prompt in the search field on the Taskbar. Now, either right-click the top result and choose 'Run as administrator' or pick it from the options listed on the right. Once inside Command Prompt, enter the following commands individually and press Enter after each one:

ipconfig /release

ipconfig /all

ipconfig /flushdns

ipconfig /renew

netsh int ip set dns

netsh winsock reset

Afterward, close the Command Prompt window and restart the computer. 

Clear the browsing cache

Clearing the cache can help with numerous browser issues. To start, open Chrome and click on the three dots icon located in the upper-right corner of the window. Then follow the steps:

  1. Select 'Settings.'
  2. Located and click on 'Advanced' to access more options.
  3. Scroll down until you have reached the 'Privacy and security' section.
  4. Locate 'Clear browsing data' and click on it.
  5. In the new window, click on the 'Advanced' tab.
  6. Select the types of data that you wish to remove. It is recommended to pick at least 'Cookies and other side data' as well as 'Cached images and files.'
  7. Select 'Hosted app data' and set the 'Time range' to 'All time.'
  8. Click 'CLEAR DATA' to initiate the removal process.
  9. After the cache has been cleaned, close Chrome and then reopen it to test if the 'ERR_SPDY_PROTOCOL_ERROR' has been fixed.