I have problems like that with the Korg USB MIDI driver and my Korg MicroX. With default configuration the editor plugin won’t work. MicroX and X50 are very similar and use the same MIDI driver.
In Korg Usb Driver Configuration I select “32 bit only” at MIDI in. So it is actually switched off for 64bit.
MicroX MIDI out shows up as microX 1 SOUND (Probably as X50 SOUND on your system). I can use now the device without problems as MIDI out device.
Bad thing is: I can’t use the controllers, keyboard and encoders of the microX. So I use the MIDI Out of the microX to a socket of my MIDI input of my sound device instead usb and leave the MIDI in socket of the microX empty. Of course I have to use the MIDI in of the connected sound card now.
But if you are lucky Korg Usb Driver Configuration is misconfigured only. Fool around with the MIDI in option. And don’t take “Configure KORG Driver Setup Utility” for “Configure KORG USB-MIDI Driver” as I mostly do. The latter is the right one.