@kdeschane your company has what we call an audit rule set up that only allows certain combinations of Project/Task and Expense Type. If the combination you entered violates this rule, you get the error message. This is something your company has configured and is not very common, which means you will need to reach out to your direct manager for help with the issue.
The only other advice I could offer is to change the combination of Project and Task for the expense entries that are showing the red exception. Likely, help from your direct manager or someone else at your company will be needed if you aren't able to get the red exceptions to go away.