ERR_SSL_PROTOCOL_ERROR: Causes and Resolutions

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ERR_SSL_PROTOCOL_ERROR is a common error that occurs while trying to access a secure website over HTTPS (Hypertext Transfer Protocol Secure). The error message is usually displayed in web browsers like Google Chrome, Mozilla Firefox, or Microsoft Edge. It indicates a problem with the SSL/TLS handshake, which establishes a secure encrypted connection between the web browser and the web server.


One of the most common causes is using an outdated web browser that does not support the latest SSL/TLS protocols. Old browsers may be unable to negotiate a secure connection with modern websites. Other causes include:

  • Misconfigurations in the SSL/TLS settings on the web server can cause compatibility issues with certain browsers, leading to a protocol error.
  • SSL/TLS certificates have an expiration date. If the certificate has expired, the browser will not trust the connection and trigger the protocol error.
  • SSL/TLS certificates are time-sensitive. If your system’s date and time are incorrect, it can cause the certificate verification to fail, resulting in the error.
  • Overzealous firewall settings or antivirus software might sometimes block SSL/TLS connections, leading to the error.
  • The web server might have SSL/TLS configuration problems, such as weak ciphers or outdated protocols, causing the error.

Read: Uptime Monitoring: Why It’s Essential For Website Performance


To begin with, ensure you are using the latest version of your web browser. Browsers regularly release updates that improve security and compatibility with modern protocols. So, check if your browser is up-to-date. Other fixes to resolve the ERR_SSL_PROTOCOL_ERROR are:

Clear Browser Cache and Check the Date and Time

Cached data in your browser can sometimes cause conflicts with SSL/TLS connections. Clear your browser’s cache and cookies, then try accessing the website again. Also, verify that your system’s date & time settings are accurate. Incorrect date & time can lead to SSL certificate validation failures.

Disable Firewall & Antivirus and Check the SSL Certificate

Temporarily disable your firewall and antivirus software to check if they are causing the issue. If the error disappears, adjust their settings to allow SSL/TLS connections. Further, if you are the website owner, check your SSL/TLS certificate to ensure it is valid and not expired. Plus, if you manage the web server, ensure that it supports modern SSL/TLS protocols (TLS 1.2 or higher) and that older, insecure versions are disabled.

Use HTTPS:// instead of HTTP://

Manually enter “https://” in the URL instead of relying on “http://”. This ensures you are using a secure connection.

Disable QUIC Protocol (Chrome Users)

In some cases, disabling the QUIC protocol in Google Chrome can resolve the issue. Type “chrome://flags/#enable-quic” in the address bar and set it to “Disabled.”

Check Server Logs

Examine the server logs for any error messages related to SSL/TLS connections. They can provide valuable insights into the root cause.

Contact Website Support

If you are a visitor and the error persists, contact the website’s support team. They may be unaware of the issue and can investigate it further.

To Sum Up 

ERR_SSL_PROTOCOL_ERROR is a common SSL/TLS handshake error that prevents secure connections to websites. By following the steps above, you can troubleshoot and resolve the issue, either as a visitor or website owner. Ensuring that your browser, system, and server configurations are up-to-date and secure will help prevent this error and ensure a safe browsing experience.

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