Appointments+ Failure to Save Service Providers

I went through the entire setup of Appointment+ with no trouble until trying to Add service providers. I select the provider, making sure they are an active user (I was actually using my user account/admin) and then selecting the service. Finally, I select the bio page and click add service provider. The page refreshes but nothing is saved and the page still has no providers listed. I have tried on multiple browsers and multiple sites on Wordpress. Specifically, this is for