This is the german forum.
If you canˋt hear the playback, then probably the routing of your mixer is wrong. From the screenshots everything looks ok. Although you unfortunately did not post the Output setup.
The last channel needs to be set to USB, and the channel should be set to „to mon“, with the monitors connected to the „Mon outs“ Jacks.
You can also connect them to main out and switch to „TO ST“ but then you might run into double monitoring and feedback loops.