Trouble no signal

Imac with 10.13.3
Serato pro
Audacity 2.3.2
Pioneer ddj-sz

Hi all, i am trying to record but don’t get any soundsignal in audacity, except for microphone… If i choose Pioneer ddj nothing
Imac has Lacie 4gb connected and Pioneer connected with Usb to Imac
I am not an IT guy so please keep it simple
Btw: with the old DDJ-RX never had a problem.
What’s wrong? (Screenshots of all settings would be welcome if someone has a solution)
Thx Patrick