Fair enough. I used the certsagenc on your server to request a new certificate for you that covers both ralfslab.net and www.ralfslab.net since the one you requested only covered ralfslab.net. I then downloaded the new certificate from the link on the left side of this page:
Here is your new certificate:
certificate.pem (1.8 KB)
Here is the CA bundle with the root certificate included:
cabundle.pem (3.7 KB)
You'll need to download your new certificate.key from your CertSage folder since I don't (and never should) have access to that.
Full certificate history for ralfslab.net:
https://crt.sh/?q=ralfslab.net