cannot add staff, categories…

Hi

i’ m looking for an appointment plugin and have installed and reviewed quite some – and uninstalled all of them.

from what i can see in the Demo Boobly seems to be the one i would like to use and probably even buy. But – i am unable to use the “+ add…” buttons in the admin pages. there literally nothng happens. I tried this with Firefox and Edge, and its the same on both browsers…

what can be the reason for that?

Greetings from Berlin, Germany

sigi