Most common cause of the symptom
You are a user of the old Insite app, Insite - Audit & Snag, and so your projects are not available to you on the new Insite Teams platform.
Other causes of the symptom
1. The project has been archived.
2. You have been removed from your project by an Admin.
Projects created on the old Insite app cannot (currently) be accessed on the new Insite Teams platform. For more information, please get in touch with us.
2. Look under the Archived projects heading and see if the project you are looking for has been archived.
3. Ask your Plan Admin to check if you are a part of the projects via the Admin Console.