Cubasis doesn‘t get input signal from Tascam Model 24

[Ev399]

Hi, i am trying to use the Model24 as an audio interface with an iPad and Cubasis 3 as DAW but
Cubasis doesn‘t get input signal from Tascam Model 24

I can route the output of the cubasis tracks to the different channels of the Tascam Model 24.

Environment
Tascam Model 24: Fw Vers. 1.63 0095
USB A to USB B —> original Apple Camera Kit Adapter —> Lightning to Apple iPad
Apple iPad: 7th generation, iPadOS 18.4 (22E240)
Cubasis 3: Ver. 3.7.5

Has anybody an idea what i am making wrong?