This can only happen in one of two ways:
- You've deleted a trainee that has accepted their course licence
- The course licence has expired and wasn't renewed
In either case, you will need to purchase a new course licence to replace the licence that was deleted or expired. You can add the existing trainee again using the form (choose Existing driver and start typing the trainee's email or username)
If you accidentally deleted a trainee that had started a course, unfortunately, this cannot be undone. If you deleted a trainee that hadn't started a course, the course licence would have been added back to your spare licences.