If you are facing any issue while applying for leaves from the ESS portal or by ASS, as shown below:

1. Available Quota is displaying as N/A or
2. Unable to apply for leave though Leave quota is added to the employee.

Though system is showing Available Quota as N/A and if you submit the form, system will show message as below ..

The reason is.. your HR need to generate the shifts for you for every month in order to apply leave. 

If you are the HR.. please refer to the below article on how to generate the shift.

ASS-Shift pattern generation