If you deleted a user by clicking the Delete button on the Users page it was just a soft delete.
This means the user's email is still present in the Good Grants database but they have been removed from your user list. Because an email can be registered only once, 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 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.