When I connect the A-300 PRO to my PC via USB, all of the control surface features work (sliders, buttons, knobs) but the keyboard doesn't seem to be sending any MIDI information.  I'm basing this on the MIDI Activity icon in the system tray.  I'm using Sonar Platinum on Windows 10.  I double checked the MIDI I/F is set to ON on the A-300.
 
Any ideas would be appreciated.

My A-800 Pro suddenly stopped sending midi note on/off data to Sonar, and Reason as well.
But it works fine with stand alone instruments.
Reason says it can't find the port the A Pro is on.
Sonar gives me no clue what the problem is.
 
I recently put the A Pro into a different USB port on my computer.
If that is the issue...like hell if I can remember which port that was.
 
Update:  Well...Hell be darned!  I remembered which port it was.  And low and behold, the port on the computer I swapped it to is blown.  How do I know this?  I swapped the Apro with my Waves key that has a blue LED on it.  When I put the Waves key back in it's original slot the light failed to illuminate.  But the Apro now functions in its original port, which is on a USB hub.  And that's where it will stay, from now until Hell Freezes Over.
 
Now...diagnosing that blown port will be my next obsession.
 

I actually figured it out about a week after i posted this.  The A-Pro has a few options for MIDI input and they are most definitely not interchangeable.  "A-pro 1" is for note data, "A-pro 2" is for control surface stuff.  "A-pro MIDI IN" is (I'm assuming) just that, the MIDI jack, but I don't use that. 
 
For some reason, my set up got scrambled.  Hope this might be able to help.
 
 

Then we are both up and running.  Good!