Clients unable to schedule any appointment

When clients try to schedule an appointment, the calendar shows an available appointment slot, but after selecting, filling out information it then bounces stating that date is no longer available. They try a different date/service and receive the same error repeatedly.
I checked my logs and there are no appointments being scheduled. I have exception dates through the 18th but all appointments after today should be available to reserve. I have 0 appointments scheduled.
Here is a video I created showing me test the site repeatedly as well as some screenshots of the back-end of the plugin and the page code used.

Thank you!