MIDI keyboard is not work with Apple M1 products

I solved it with MIDI-Din to USB cable

Important note: midi keyboard needs to be powered from a separate power supply

Whenever I plugged in, I could see a message for allowing the USB device, and I could see it in Midi Studio as attached:

When I tried to test the midi setup, I couldn't see any incoming signal on the icon.

Actually, I was not using an adapter while playing the keyboard on a Macbook with an Intel chip and a 2nd generation iPad.

However, when I tried it without an adapter on M1 Macbook and iPad, the keyboard light was on but no sound was coming out.

In some forums, it is recommended to use a compatible adapter, it says 9V 0.5 A at the socket input of the midi keyboard, so I bought a regulated adapter with adjustable volts and adjusted it accordingly. But still no sound comes out.

The keyboard has a USB-B output. I could convert USB B to USB-A via a cable and use it on old Macbooks and iPads.

On non-M1 USB-C iPads, I use an adapter that converts USB A to USB C.

But although the keyboard works on the iPad Pro 2018 with this adapter and cable, it does not work on the iPad Air 5 M1.

-even this much is complete nonsense-

I also used a power adapter thinking it would be powering via USB, but it still didn't show up.