Appointments+ Next Month button not working

I have installed and setup Appointments+ and it is working fine. However, it is not showing the next month of the calendar when I click on the Next Month button.
I have turned off all my plugins to ensure that its not a conflict with one of my plugins but the error persisted. I also set the pagination code as follows: [app_pagination step="1" month="1"]
Appointments page is here:
The website is on maintenance mode but I can temporarily load it up for this fix. I would appreciate any help that could be provided to fix this issue as the deadline for the website launch is the end of this week.