2.20.22. ERR_SPDY_PROTOCOL_ERROR error

The problem can be observed in Chromium-based browsers (Chrome, Opera, Vivaldi, Brave, Yandex Browser, Amigo and others) running on devices that use anti-virus programs like AVG or Avast, especially when using an SSL connection.

• If you are using any of the antivirus programs¹⁾, try disabling HTTPS scanning in it or adding the error site to exceptions. For example, to add a site to the exclusions in Avast, do the following:
  1. Go to the section "Settings» («Settings»).
  2. You take "Active protection» («Active Protection»).
  3. Open "Web screen settings» («Web Shield Protection»).
  4. In section "Exceptions»Add the sites where the error occurs.
  5. Check for an error.
• Try to clear the socket pool in Chrome:
  • Enter in the browser address bar chrome://net-internals/#sockets.
  • Click "Flush socket pool»:
  • Restart your browser and check for the error.
• Try flush DNS cache.
• Try clear browser cache.