After Cancel Appt Checkbox clicked nothing happens

I successfully was able to get the cancel button to appear on the clients’ page but nothing happens when they click that button?

In the general plugin settings I am allowing (yes) clients to cancel their own appointments.

The shortcode I am using to display the clients’ appointments to them is:

[app_my_appointments order_by=”start” strict=”1″ allow_cancel=”1″]

Here is a screen shot of what is being displayed:

Screenshot

Not sure how the clients can actually cancel the lesson

Any ideas as to what is going on?