After moving my studio, I've run into this issue when setting everything back up. Reaper recognizes the A61 controller via USB, I've installed all the NI and Reaper updates. However, when I open Kontakt as a plugin within a session, once I load any instrument from the library, the keyboard will not control the software. Clicking on the keys shown on the monitor does "play" the chosen sound, but the controller does not.
I've researched the MIDI 2.0 issues others have had in Windows 11, I've also updated all the C++ patches as well. I'm looking for other ways to troubleshoot this so I can get everything operating again - any guidance would be very much appreciated.