Fix setup SSL Certificate to POP3 Mail Server in WHM and connect domain account in GMAIL

I need someone urgently to fix setup / install SSL certificate (will be provided) into POP3 mail server correctly in WHM control panel so that it should work in receiving emails using the domain address, for example. [login to view URL] email address can be received in POP3. In addition, I also would like to have the domain email account to be added/setup into the GMAIL additional accounts to receive emails that are addressed to that domain email addresses (this is usually through POP3). Also make sure the GMAIL receives emails through POP3 (SMTP is already working fine) Currently I have additional accounts setup in GMAIL that connects to pop3 mail server on domain through SSL connections, however, GMAIL detects there is error in server "Unable to establish secure SSL connection to server" .