Normally when delete user at 3DPassport , it will not allowed the user to be recreated. at “3DPassport Control Center” , audit -> User, search the deleted user
When you delete user , you can also choose to archive email. so below picture shows email and username both not allowed to reuse again.

To solve this issue. delete the account from “X3DPASSADMIN”.”USERS_OLD”
DELETE FROM "X3DPASSADMIN"."USERS_OLD" WHERE DS_USERNAME='YourUserToBeDeleted';
commit;
After executing this , in audit , you can not search the user again.

the user can be created again. use 3dpassport to register 🙂