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Why Really Simple SSL Might Not Detect Your Certificate (And How to Fix It)

19 threads Sep 16, 2025 Plugin → Really simple security

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One of the most common issues users encounter with the Really Simple SSL plugin is the dreaded "No SSL certificate detected" message, even when a valid certificate is installed on the server. This can be a confusing and frustrating experience, especially when your hosting provider confirms the certificate is active. Based on community reports and troubleshooting threads, this guide explains the typical reasons for this detection failure and provides actionable solutions.

Why This Happens

The Really Simple SSL plugin operates by checking your server's configuration to detect an active SSL certificate. It does not install or manage the certificate files itself; it configures your WordPress site to use the certificate that your web server (e.g., Apache, Nginx) is already presenting. The detection process can fail for several reasons:

  • Certificate Mismatch: The domain your WordPress site is configured to use (e.g., www.example.com) does not exactly match the domain listed on the certificate (e.g., example.com).
  • Manual Certificate Installation: If you installed a certificate manually (e.g., via command line with Certbot, or by uploading files), the plugin may not be able to automatically detect the new certificate's path if the server configuration wasn't updated to point to it.
  • Non-Standard Hosting Environments: Self-hosted setups, NAS devices, or complex server configurations often fall outside the standard hosting panels (like cPanel) that the plugin is designed to recognize.
  • Multi-Domain or Wildcard Certificates: While these certificates cover multiple domains, the plugin's initial detection might only validate against the site's primary domain, sometimes causing a false negative for additional domains (SANs) on the same cert.
  • Port or Firewall Issues: The SSL port (443) may be closed on your server, preventing the plugin from successfully checking for a certificate.

Common Solutions

1. Verify Your Certificate is Active and Correct

Before troubleshooting the plugin, always confirm your certificate is installed correctly and is valid. Use a third-party tool like SSL Labs' SSL Test. Enter your domain to get a detailed report. If the tool confirms a valid certificate is in place, the issue is likely one of detection, not installation.

2. Ensure Your WordPress Address and Site Address Match the Certificate

This is a critical step. In your WordPress dashboard, go to Settings > General. Both the WordPress Address (URL) and Site Address (URL) must exactly match the domain name on your SSL certificate. For example, if your certificate is for example.com, your addresses cannot be set to www.example.com, and vice versa. A mismatch is a frequent cause of detection problems.

3. Configure Your Web Server Correctly

Since Really Simple SSL reads the certificate configured in your web server, you must ensure the server is pointing to the correct certificate files. This process varies by server software (Apache, Nginx).

  • For Apache: The certificate and key paths are defined in the virtual host file, typically within <VirtualHost *:443> directives using SSLCertificateFile and SSLCertificateKeyFile.
  • For Nginx: The paths are set in the server block for port 443 using the ssl_certificate and ssl_certificate_key directives.

After modifying your server configuration, always restart the web service (e.g., sudo systemctl restart apache2 or sudo systemctl restart nginx).

4. Use the "Force SSL" Override

If you are absolutely certain your certificate is valid and correctly installed on the server, but the plugin still fails to detect it, you can override the detection. In your WordPress wp-config.php file, add the following line above the /* That's all, stop editing! Happy publishing. */ comment:

define('RLRSSSL_FORCE_ACTIVATE_SSL', true);

This directive will force the plugin to activate SSL settings, bypassing the certificate detection check. Use this as a last resort.

5. Check for Port 443 and Firewall Settings

Ensure that port 443 is open on your server and that any firewall (e.g., UFW, iptables, or a cloud hosting firewall) is configured to allow HTTPS traffic. A closed port will prevent any external tool, including the plugin, from verifying your certificate.

When a Wildcard Certificate is Needed

If you are running a WordPress multisite network with subdomains (e.g., shop.example.com, blog.example.com), a standard single-domain certificate will not be sufficient. You will need a wildcard certificate (e.g., *.example.com) to cover all possible subdomains. The Really Simple SSL team suggests using DNS verification during the Let's Encrypt process to generate a wildcard certificate. Alternatively, your hosting provider may offer wildcard certificates.

Remember, the plugin's primary role is to configure WordPress to use the SSL certificate provided by your server. Ensuring that certificate is correctly installed and matches your site's domain is the foundational first step to resolving most detection issues.

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