I need help getting my MIDI keyboard to work with SONAR.
 
I'm using an older AKAI MPK49 MIDI keyboard as an input to SONAR Instruments. Currently I have Lounge Lizard loaded. Lounge Lizard plays fine when I use my mouse to play the keyboard on it's popup.
 
I've verified the keyboard is selected as the MIDI input device and I've selected the Omni input from all MPK49 inputs to be sure I'm not missing any possibilities. I've also tried the Omni input individually from all 3 MPK49 MIDI outputs. The input indicator on the little MIDI icon in the system tray blinks when I hit a key on the MPK49 and SONAR's MIDI connection lost dialog pops up when I disconnect the MPK49 USB cable, but Lounge Lizard is not receiving MIDI commands from the MPK49.
 
The MPK49 works fine with stand alone instruments but not with SONAR.
 
I'm using SONAR Version: 23.8.0 BUILD 30 [2017-08] - x64.

If the MIDI activity indicator is lighting every time you press a key, then likely the problem is not with the connection itself. How do you know that your softsynth is not receiving MIDI messages from SONAR? If the problem is, as I suspect, that you are not hearing the synth or not seeing a waveform, then most likely it is not a MIDI connection problem, but a SONAR routing problem. Work your way through tutorial #4 in the Reference Guide or web help at:
https://www.cakewalk.com/Documentation?product=SONAR&language=3&help=Tutorial4.1.html 
 
 

 
Turn on Input Echo.
 
"...The input indicator on the little MIDI icon in the system tray blinks when I hit a key on the MPK49 and SONAR's MIDI connection lost dialog pops up when I disconnect the MPK49 USB cable."
 
This tells you the problem is not a cabling or MIDI interface issue. Make sure the Input selector is set to the correct device, initially in Omni for simplicity. Then click the red circle button to enable recording on the MIDI track, press "R" and hit some notes. You should see some dots appear in the MIDI track, and when you hit play Lounge Lizard should make some sound.
 
If that's all working, but you just don't hear anything when you play in real time, then the problem is that you're simply not turning on Input Echo.

Well, today when I started up my PC and launched SONAR, Lounge Lizard worked with the MPK49. I didn't have to change anything. I had closed and opened SONAR several times yesterday which didn't solve the problem, but it's solved now. I don't have a clue what was wrong. I found the two responses I received helpful and worked through them to see if I could find any problems with the synth setup.
 

slartabartfast
Work your way through tutorial #4 in the Reference Guide or web help at:
https://www.cakewalk.com/Documentation?product=SONAR&language=3&help=Tutorial4.1.html 

Thanks slartabartfast, I ran through my setup using the tutorial as a reference and didn't find any problems with what I'd done.
 

bitflipper
 Turn on Input Echo.
 
Make sure the Input selector is set to the correct device, initially in Omni for simplicity. Then click the red circle button to enable recording on the MIDI track, press "R" and hit some notes. You should see some dots appear in the MIDI track, and when you hit play Lounge Lizard should make some sound.
 
If that's all working, but you just don't hear anything when you play in real time, then the problem is that you're simply not turning on Input Echo.

Thanks bitflipper. The input echo was on and that's all I needed to hear the synth. I went through the record steps you suggested to be sure things were working and recorded a short midi clip. So it looks like the problem, what ever it was, was either intermittent (hope not) or was fixed by restarting my PC.