Install Self-Signed Certificate to Hostname.
1) Login to WHM as a root user.
2) Go to “Service Configuration”.
3) Then select the following services and click on “Browse Certificate”.
Calendar, cPanel, WebDisk, Webmail, and WHM Services
Dovecot Mail Server
Exim (SMTP) Server
FTP Server
4) Select hostname and click on “Use Certificates”.
5) Then click on “Install”.