In order to have access to the EasyLink Messaging System, a Customer Account Number (CAN) needs to be created and User Account Numbers (UAN) must be created. The CAN cannot be used to log in to the system but is basically a container for UAN's so a CAN holds all of the UAN's. Only UAN’s can be used to log into the system and each UAN is assigned to a CAN. A Customer Account Number (CAN) can contain multiple User Accounts (UAN's) which contain information about Users of the EasyLink Messaging System. The CAN is associated to the customer and contains information about the customer that will be used for billing purposes.
Please see the attached document for more information.