When you send an email with SimplyCast it must comply with the CAN-SPAM Act of 2003. One of the requirements of the Act is that commercial emails must have the physical or mailing address of the sender, or the third party whose products are being promoted in the email.
The address can be edited by clicking on the footer at the bottom of the email in the Simple Editor. In the Advanced HTML editor the address can be edited in the menu on the left of the screen.
You will not be able to send the email if you have an incomplete or hidden address at the bottom of the email.