If you are unable to find your email address in the From field within Send Message, it could be that it either hasn’t been created or hasn’t been validated:
Go to Communications Summary.
Find your name on the User emails widget and check the Status.
Click the link Not Set/Verified to review the configuration.
From within the Outgoing Email Settings screen. If the email account is showing:
Not verified then select Edit and make sure all details are correct, then select Email Passcode.
For more information on Outgoing email settings see KB 3212 SMTP Setup Information
For more information on Communications Centre, please see KB3199 Communications Centre: Collateral.