If you see the following:
Error Message:
It is not possible to create this user as another account exists with the same username, within your company.
How to fix it:
Ask the user’s previous employer to remove their account from Atlas.
Once removed, you can register the user with your company.
or
Enter a new username or email for the user
Many email addresses will allow you to use sub-addressing, often referred to as "the plus (+) trick" to add a tag (+tag) before the @ symbol of your email address to create unlimited, functional aliases. Emails sent to these addresses go to your main inbox, but can easily be filtered, and identified.