Learn how to fix‘ ERR_SSL_PROTOCOL_ERROR’ in cPanel. Our cPanel Support team is here to help you with your questions and concerns.

How to Fix ‘ERR_SSL_PROTOCOL_ERROR’ in cPanel

The ‘ERR_SSL_PROTOCOL_ERROR’ is a common faced by tech professionals and regular users alike.

It indicates a failure to establish a secure connection between a client (browser) and a server due to SSL misconfigurations.

Since SSL ensures encrypted communication between web browsers and servers, this error can expose potential vulnerabilities. Hence we need to resolve this error as soon as possible.

In this blog, we will explore how the error looks across different browsers, common causes, and how to troubleshoot it, particularly within a cPanel environment.

An Overview:

1. How ‘ERR_SSL_PROTOCOL_ERROR’ Appears in Different Browsers
2. Causes of ‘ERR_SSL_PROTOCOL_ERROR’ in cPanel
3. Troubleshooting the ‘ERR_SSL_PROTOCOL_ERROR’

How ‘ERR_SSL_PROTOCOL_ERROR’ Appears in Different Browsers

Though the error message varies across browsers, its core meaning remains the same. Here’s a breakdown:

• Google Chrome:

  ”This site can’t provide a secure connection” alongside the ‘ERR_SSL_PROTOCOL_ERROR’ code.
• Mozilla Firefox:

  “Secure Connection Failed,” along with a detailed error: “An error occurred during a connection to [website]. SSL received a record that exceeded the maximum permissible length.”
• Microsoft Edge:

  “Error Code: DLG_FLAGS_SEC_CERT_CN_INVALID” with warnings about invalid security certificates or domain mismatches.
• Safari:

  “Cannot Open Page,” with an additional note saying, “Safari can’t open the page because it couldn’t establish a secure connection to the server.”

While the error may look similar to other connection issues like ‘ERR_TOO_MANY_REDIRECTS’, we need to check if the root cause is SSL misconfigurations or protocol incompatibilities.

Causes of ‘ERR_SSL_PROTOCOL_ERROR’ in cPanel

Below are the most common reasons for this error when managing websites via cPanel, along with their solutions:

Misconfigured SSL Certificate:

An improperly installed SSL certificate, incomplete certificate chain, or expired certificate can trigger this error.

Fix: Ensure the SSL certificate and its chain, including root and intermediate certificates, are installed correctly in cPanel.

Furthermore, confirm the SSL certificate hasn’t expired, been revoked, or is otherwise invalid. If expired, renew the certificate.

We can also use AutoSSL in cPanel to automate the management and renewal of SSL certificates.

Outdated or Incompatible TLS Versions:

The server may be using older TLS versions that modern browsers no longer support, such as TLS 1.0 or 1.1.

Fix: Configure the server to use the latest TLS versions through cPanel’s WHM under the “Apache Configuration” settings.

Also, disable older protocols like SSL 2.0, SSL 3.0, TLS 1.0, and TLS 1.1 to avoid compatibility issues.

Browser or System Date and Time Issues:

Incorrect date and time settings on the client device can lead to SSL errors, as browsers may reject SSL certificates they perceive as expired or not yet valid.

Fix: Ensure that the user’s system is set to the correct date and time.

Additionally, clear the browser’s cache to ensure it doesn’t load an outdated SSL certificate.

Firewall or Security Software Interference:

Firewalls, antivirus, or proxy settings can sometimes block or interfere with the SSL handshake process, leading to protocol errors.

Fix: Temporarily disable firewalls or antivirus software to determine if they are the source of the issue. Adjust the settings to allow SSL traffic if necessary.

Additionally, ensure that proxy settings aren’t blocking SSL/TLS connections.

Server-Side Configuration Errors:

Misconfigured server settings, such as errors in Apache or NGINX configuration, can also cause SSL protocol issues.

Fix: Review the SSL settings in the server configuration files. Ensure that the VirtualHost blocks (Apache) or server blocks (NGINX) are properly configured.

Then, apply the new configuration by restarting the web server.

Issues with SSL Redirects:

Misconfigured redirects from HTTP to HTTPS can result in infinite redirect loops or attempts to redirect to non-existent SSL-enabled domains.

Fix: Review the `.htaccess` file for any faulty redirect rules that could cause SSL problems.

Also, ensure that all domains and subdomains are configured with valid SSL certificates and that redirects point to SSL-enabled URLs.

Expired CA Root Certificate:

If the root certificate of the issuing Certificate Authority is expired or unrecognized, browsers may reject the SSL certificate.

Fix: Ensure that both server and client CA root certificates are up to date. This may require operating system or browser updates.

If necessary, reinstall the SSL certificate with an updated root or intermediate certificate from the CA.

Troubleshooting the ‘ERR_SSL_PROTOCOL_ERROR’

To diagnose and fix SSL protocol errors, follow these steps:

• Online tools like SSL Labs’ SSL Test can provide a detailed analysis of our SSL configuration, helping pinpoint potential issues.
• Checking SSL error logs in cPanel can give us more specific clues about what’s causing the problem.
• Try accessing the website from different browsers or devices to see if the issue is isolated to one browser or widespread.

[Need assistance with a different issue? Our team is available 24/7.]

Conclusion

Addressing the ‘ERR_SSL_PROTOCOL_ERROR’ helps maintain secure and reliable web communication. By understanding the error across different browsers, identifying its root causes, and applying effective solutions within cPanel, we can resolve the issue promptly and ensure that our SSL setup is robust and secure.

In brief, our Support Experts demonstrated how to fix ‘ERR_SSL_PROTOCOL_ERROR’ in cPanel.