Once you have your certificate exported to the Ubuntu server (normally your certificate will have a .pfx extension) you need to convert it to a .pem extension:
openssl pkcs12 -in AxigenCert.pfx -out /var/opt/axigen/AxigenCert.pem -nodes
You will be prompted for the password you entered when you exported the certificate. You have to enter “-nodes” so that you won’t be prompted for a passphrase, the certificate will not work with Axigen if you enter a passphrase. “/var/opt/axigen” is the default path where Axigen keeps its .pem files.
Next you have to configure each service(POP,IMAP,Webmail,etc.) to use SSL:
Now you Services are SSL encrypted.