If you see the following Error Message:
The selected date range is either public holiday, non-working day, or both.
This means that the day requested is tracked as a non-working day for the employee. You can either change the date of the request, or you can adjust their Working day profile, if it is in correct.
How to fix it:
Update the employee’s Working Day Profile:
Employees/workers > Manage > Employee record > Job tab > Update > Change Working Day Profile
Change the time off request for a day that the employee is scheduled to work.
Advise the employee that they are not scheduled to work that day.