If you are unable to drag and drop an appointment or a block out time, check for the following:
Check if the zoom on the browser is more than 100%.
If the browser zoom is more than 100%, reset the zoom to 100% and try to move the appointment or the block out time.
Check the column width and row heights in the Appointment Book.
Sometimes, if you have increased the appointment width and height in the Appointment Book, you might be unable to move an appointment or block out time.
Reset the Height and Width sliders by dragging them to the left and try to move the appointment or the block out time.