Software Development:
Individual Programming

Symptom

You have installed a Let’s Encrypt SSL certificate, yet the web browser displays a warning when you use https:// connections:

www.[domain] is using an invalid security certificate.
This certicifacte is only valid for [domain]. Error code: SSL_ERROR_BAD_CERT_DOMAIN

The warning may be worded slightly different, depending on the type of browser you use.

Cause

When you first installed your Let’s Encrypt SSL certificate you did not check the box that adds the www prefix to the domain name. Your certificate was only issued for your domain without www prefix, e.g. https://[domain], but not https://www.[domain].

Solution

1. Log into the webspace control panel.

2. Click on the “Websites & Domains” menu.

3. Click on the "SSL/TLS certificates" icon.

4. Click on the "Reissue Certificate" button.

5. In the “Entry-level protection” section, click on the “Get it free” button.

6. Check the checkboxes " Include a ‘www’ subdomain for the domain and each selected alias " and "Secure webmail on this domain".

7. Click on the "Get it free" button.

Overview of frequently asked questions