We do support TLS and SSL for our Corporate Email plan or above.
To setup the secure connection in Thunderbird 2.0, we can
1. Open Thunderbird, ThunderBird
2. Tools > accounts > server settings
3. Change the mail server address e.g. mail.domainname.xyz (in our hosting environment, default name for POP3, IMAP and SMTP servers would be mail.domain.com)
4. If you want to use SSL, update the Port value to 993 for IMAP / Update the Port value to 995 for POP
If you want to use TLS, update the Port value to 994 for IMAP / Update the Port value to 996 for POP
5. In the Security Settings section, select SSL/TLS from the Use secure connection options.
6. Click Outgoing Server (SMTP) in the folder list.
7. Select the entry from the list and click Edit. The SMTP Server page appears.
8. Change the mail server address
9. If you want to use SSL, update the Port value to 465
If you want to use TLS, update the Port value to 587