How to display a message when there is no policy rate for a given expense item date?

Summary:
Employees are not able to submit mileage expenses when there is no rate for the expense item date they want to enter the expense for. They can not choose a fuel type, so they get an error message on the 'required field' but that is confusing. It should be a message saying 'no rate'

Content (please ensure you mask any confidential information):

Expenses

Version (include the version you are using, if applicable):

24A

Code Snippet (add any code snippets that support your topic, if applicable):