Log into Cloud Control and do the following ...
- From the System section, click Domains.
- Click on Add Domain
- Choose whether you're adding a Domain or a Sub-domain. In most cases, you will choose Domain
- Enter the name of the domain in the Name field.
- Click Add Domain or click Cancel to disregard all changes.
- Now scroll to the Organization section, and click Domains.
- Click Add New Domain, select the domain to be added as an Accepted Domain for Exchange and click Add Domain.
Your domain will now be available to use against all objects in your Exchange configuration.