In System > HTTPS, under the Connection Type dropdown list, switch to Secure:
System > HTTPS
The Certificate Configurator window should appear. Here you can generate a self-signed certificate, or import an already existing certificate. You can also change the existing certificate and start using a different one.
To generate a new certificate, make sure the Generate Self-Signed Certificate radio box is checked and click Finish. A confirmation to restart the CallReplay service will appear.
To check the new connection type, open a web browser and go to https://IP_OF_RECORDER/. If the certificate is not signed by a CA authority, you will most likely need to explicitely tell the browser to accept the public certificate: