Whether or not you choose to remain in the sandbox, you will need validate at least one email address to use as your from_email address before you can send any email through SES. In the SES console selec the Email Addresses option from the left hand menu. On this screen there should be a blue button prompting you to "Verify a New Email Address". Click on this button to proceed through the validation process. Once your from email address has been validated, please note the address for later configuration use.