Salam Ramadhan, 

During fasting month, delivery availabilities will be severely affected between 4pm to 8pm, due to amount of delivery requests our service partners will be receiving in that time frame. In order to ensure no disruption to your orders, you can adjust your time-slot to limit customers from choosing those time frame.

To do this, simply adjust your current daily time slots, by setting "To" to 4:00pm. Next, add another time slot, and choose the same day, and set "From" to 8:00pm, and "To" to your closing time, if you're still operating after 8pm. You will have 2 rows of same days, as they indicate 2 different session of the same day.

Here are en example how one of the shop is using multiple session time slot to disable 5pm to 8pm time frame: