Step 1:

When you enter your domain as the server name for a secure connection, you will get a certification error in your email client, because the certificate is not issued to your domain name.

In order to establish a secure connection to your email accounts, please only use the following data for incoming and outgoing email server:

<your-login>.kasserver.com

Please replace <your-login> with your own KAS username. You can find the necessary data directly inside your KAS (Technical Administration) panel under the menu item Email -> Email Account.