DIGITAKT does not midi over USB

Good morning,
I’m a newbee here. Got my used DIGITAKT and have started to work with. I’ve tried to sequenz my analog synths over USB but it does not work. The DT ist connected with USB to my PC and I can build up a connection in the Transfer-Tool. It is running with OS 1.20A nd Win 10 Server. I’ve tried out all the things read in this forum, multichannel 14, setting midi to usb or midi usb, mapped the chanel …
If i start MIDI-OX on the PC to see, which MIDI ports are sending, the DT hangs up.

Than I’ve disconnect USB and connected all my gear with MIDI everything works fine. Is it normal?

Have a fine day and stay healthy