You might have attempted to delete a project from Project Server but it still shows up somewhere. In this case you may have to simply delete it from the publish database. Here is how.
- Log in your PWA
- Under Settings, click on Server Settings
- Under Database Administration, click on Delete Enterprise Objects
- Select 'Projects' and 'Delete projects only from Published database'
- Select the project you want to delete
- Click on 'Delete' button and wait few minutes.
This operation normally requires Admin or CAM privilege on the PWA.