Book Instructor & Add Availability Schedule not working

I have just added the big blue button plugin and have done the setup as per the instructions. When I click on book instructor from the course panel, I am able to view the calendar, but when I directly go to the instructor and try to click on the Book Instructor, i am getting an error page of 404 I have enabled the "Enable Appointment" under settings > General, but still nothing is happening. Apart from above, when I try to "Add Availability Schedule" under Schedule Calendar, after clicking the Set date or Set time, nothing is coming. Need the solution urgently as I need to present the demo tomorrow morning.