If you cannot find a Project ID in the Services Window Settings, or if you observe a mis-match in Project IDs, this may be due to you upgrading a project using an older version of Unity, or by creating a new project while offline. You can remedy this by linking your Analytics project to your project in the Editor.
Is something described here not working as you expect it to? It might be a Known Issue. Please check with the Issue Tracker at issuetracker.unity3d.com.