Login to the CloudBlue portal: https://portal.cloudnet.services/
Click Customers at the left side of your screen.
Find the customer you wish to find the username from.
Click LOG IN / LOG ON next to the customer name.
Click Deluxe Marketing Suite at the left side of your screen.
You will find your username here, and an option to reset your password.
Note: If your customer has more than one subscription, the username will be the same for all subscriptions.