Hello, This is probably a conflict on your Site, something from your Theme ( or another Plugin) could be ‘blocking’ our dropdown functionality.
1. Please try this first.
Go to the main plugin settings, and disable/uncheck option “Include full bootstrap front-end“, but also uncheck the other option “Include full bootstrap on back-end” as well.
Then refresh the page, and check if dropdowns are now working.
2. If the issue is the same after this, can you please try changing your current WP Theme to any other, such as any default WP Theme, and see if the dropdowns start working after that? Let us know how it goes. Thank you.