When accessing webmail at https://yourdomain.com/webmail you will be redirected to a SSL secured address and your connection will be encrypted. You will receive security warnings because the SSL used is a self-signed one and not a commercial one. Kindly accept the certificate and click on ""I Understand the Risks" and "Add expection". Once you have added the expectionthen you need to confirm the security check and webmail will be accessible.
The above procedure is for Firefox web browse. Kindly check the documentation for your corresponding browser on making secure connection through it.
