With the release of iOS 13, Apple has improved the system security and privacy by giving users the option to disable Bluetooth and Location access for apps. After the update, users will find alert pop up such as "App Would Like to Use Bluetooth" when open apps.
Remember to choose "OK" when you open ZUS app the first time after the system update. This is due to most of the ZUS devices require Bluetooth connection to enable functions. But, if you accidentally click on "Don't Allow", you can still grant the Bluetooth permission by going to Settings > Find "
ZUS app" > Open Bluetooth Sharing.
As for location service, ZUS app also needs users to "Always" allow access. It's normal if users receive the pop-up window suggest multiple location access alert. You can simply choose "Always Allow". Also, you can always give location access permission for ZUS app by going to Settings > Privacy > Location Services > Find ZUS app > Choose "Always".