You can check the webmail for any account by logging into https://orlandocosplay.com:2096 with the full username (user@domain.com) and password for the email account.

To check your mail through a desktop application, you will need to configure the application. Your mail server is most likely "mail" (e.g. mail.orlandocosplay.com. You will need to use the full username (user@domain.com) and password when configuring your account from an email client. It is a good idea to check "My Server Requires Authentication" as most mail servers require this option.