The USB Port on the NP12 is designed to communicate with a “host” product (computer or iOS device) you cannot connect directly to anything but a computer or iOS type device.

As you say, the NP11 has Midi in/out jacks. which will allow you to connect it directly to the YC61. The NP12 - like so many of the more recent keyboards - only has a USB to Host connection. You will need to a use a MIDI USB Host converter - like this one : https://kentonuk.com/product/midi-usb-host-mkii/ to connect the NP12 to the YC61.
That's the model I used to connect my P.105 and it works fine.
I have seen a cheaper one here: https://www.dv247.com/en_GB/GBP/Miditech-USB-MIDI-HOST/art-SYN0006178-000?campaign=GShopping/UK&ProgramUUID=HADAqJarPzAAAAFlea9yjI.G&gclid=EAIaIQobChMIxsmH_8656gIViu3tCh0F-gqYEAQYASABEgJsG_D_BwE but I haven't tried that one.
It should work OK

i just hooked it into my Modx no problem

In the settings there's an option for USB to be MIDI or stay USB but perhaps that's only for a computer host.

Use MIDI cables and it should work fine as long as you set the internal controls for the MIDI option as you desire.

I think the YC default is both internal and external control. Make sure your cables are in to out & out to in etc.

Oh I see the NP12 doesn't have MIDI I/Os. That sucks.Use the hub then.

i just hooked it into my Modx no problem

MODX can act as a USB host (as of the 2.0 update). YC61 does not have that feature. If you're not using a computer or iOS device, you'd need to use some other host adapter. Besides the ones from Kenton and Miditech that Jon mentioned, there are also these:

https://www.amazon.com/Midiplus-USB-MIDI-Host-midiplus/dp/B074NGTGHN

https://www.excelvalley.com/product/midi-usb-din-converter/

http://compasflamenco.com/midi-c-3/usb-host-midi-2-p-6.html

https://www.juno.co.uk/products/mode-machines-cerebel-usb-to-midi-serial/564328-01/

I'd just stick with his NP11. 😉

yup luckily i had sold my np11 to my neighbor and traded it back

i call her Frank-Keyz