Hi Harvey2378k,
When Cubasis is started for the first time, a pop up asks for the permission to use the microphone.
Please double check that the permission is given, in order to use Cubasis with external audio devices.
- Please go to the iOS settings
- Please go to Privacy → Microphone
Please make sure that the Microphone option is enabled for Cubasis
Hope that helps to solve the problem.
Best,
Lars