When booking leave there will be reasons as to why the leave request may not use any allowance. Below are some of the reason why...
Holiday showing as Zero
If you have a person who has booked leave and the amount of holiday used for the entry is '0' then there may be a good reason for this.
It's worth double checking the following
Does the day fall on a day they do not work?
If they receive Bank/Statutory holidays whether their booked leave coincides with one?
If there is a company holiday booked? Click here to take a look : Company Holidays
If the employee has 'ignore working pattern' ticked, they have to manually input the correct days off.
If you believe one of the reasons above is causing this issue, simply double check and ask the employee to re-book the days.