If you are a Job Admin, you can see only candidates who are on jobs where you have been assigned permissions. If you attempt to search for a candidate who is on a job where you have not been assigned permissions, you will not see the candidate returned in your search results.
Job Admins can view candidates on jobs with any status (Open, Draft, Closed).
If your team has not granted you permission for any specific jobs, you won't be able to view any candidates in Greenhouse Recruiting.
To update your permissions, reach out to your Site Admin and ask them to update your account. If you are unsure which user to contact, check your in-house contacts.