If you deleted a user by clicking the delete option in the Action drop-down on the Users page, it was just a soft delete. If you've soft deleted the user's email, it is still present in the Good Grants database but has simply been removed from your user list. Because an email address can be registered only once within the platform, they still exist in our database and you won't be able to add them back as a new user.
However, you can undelete them by going to Users and selecting Deleted from the drop-down menu at the top.
Select the user you want to undelete, open the Action drop-down, and then click the Undelete button.
If you want to permanently delete a user you'll need to click on their name in Users and then click the Delete this user permanently button.
Please refer to our guide for more information on permanently deleting a user.