How to configure S/MIME encryption with your zMailCloud account

How to configure S/MIME encryption with your zMailCloud account
zMailCloud S/MIME allows users to sign and encrypt messages. It's available upon request to all customers at no charge. If you'd like it enabled for your domain, please submit a ticket.
1. Once S/MIME encryption is enabled on your account, you must obtain a certificate from a Certificate Authority (i.e. Comodo, McAfee, etc). There is a free certificate Comodo provides for personal use only at: or you can purchase certificates for commercial use from these authorities:
2. Download and install the certificate to your computer.
IMPORTANT NOTE: We do not offer installation of your S/MIME certificate.
3. Download Java if it's not already installed. Java 1.6 or higher is required to use the S/MIME feature. Java is a free download available for Windows, Mac and Linux at
  • Once Java is installed or updated, you will need to add an exception for your custom URL in Java's security settings.  To do so, click Start >> Control Panel >> Java (or search for java in the control panel search bar)
  • smime_1.png
  • Click, the 'security' tab, and under the exception site list section, click "edit site list"
  • smime_2.png
  • Click on add, and enter in your custom URL.  Then, click "OK".
  • smime_3.png

*If you don't know your custom server hostname, please contact your Domain Administrator, or the help desk.

  • Click "OK" to close the Java control Panel.
4. Once your certificate is installed in your web browser, login to your web client account and compose a new message.  You may receive a message asking to allow Java to run.
5. When sending your first message to a recipient, It is preferred to sign a message first to your intended recipient, so they can get your certificate on file.  Click on the "Don't Sign" drop down from the compose menu bar and choose the option to sign your message
6. To send an encrypted message, please select "Sign and Encrypt" from the "Don't Sign" drop down as seen in step 3. You must also obtain your recipient's certificate prior to sending them encrypted messages. If not, your messages will appear unreadable to your recipient. Their certificates are stored in your Address Book.

If you require any additional assistance in configuring apple mail with your zMailCloud account.  Please contact the help desk via:

phone: 1-888-962-4525


AOL Instant messanger:

Help Desk ticket


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