Hi, I have newly installed Cakewalk Sonar Platinum 21.10, and I have high latency on echo sound of midi keyboard. Maybe around 300 ms. I setted driver mode ASIO, then MME 32bit, but nothing changed. I also changed mixing latency, but it is the same. What I would do for solving it? 
Ryzen 5 1600, 2x8GB 3000 MHz RAM CL15, Samsung 960 PRO 512GB, MSI B350 Gaming Pro Carbon

We need some more information...
 

1. What audio interface are you using?
2. What virtual instrument are you triggering?
3. Are you using any audio effects?

Anderton
We need some more information...
 

1. What audio interface are you using?
2. What virtual instrument are you triggering?
3. Are you using any audio effects?

I have Scarlett 6i6 sound card and MIDI device is Kurzweil pc3le8. I have not turned on any special effects, just clean piano sound. Only that presset, what is there after sonar starts. Nothing added, as you can see at picture below. 

is there a buffer setting on your soundcard? if so,
lower the buffer  then run the wave-profiler & adjust the latency in sonar.
 
hth 
martin

Also make sure you have the latest Focusrite drivers. Many a thread that relates to problems with Focusrite interfaces end with downloading the most recent drivers.
 
You mentioned changing the mixing latency, what is it set at currently?

The only time I get that is if I forget to bypass a "look ahead" effect like the LP 64 multiband. 
 
Does the keyboard have a MIDI driver for USB or are you using the 6i6 Midi ports? 
Make sure to use all the latest drivers for these devices. 
You should always use ASIO mode the 6i6 is rock solid for me. 
I set my MIDI buffer at over 1,000. The scarlett I use a medium buffer setting of 7. 

Cactus Music
The only time I get that is if I forget to bypass a "look ahead" effect like the LP 64 multiband. 
 
Does the keyboard have a MIDI driver for USB or are you using the 6i6 Midi ports? 
Make sure to use all the latest drivers for these devices. 
You should always use ASIO mode the 6i6 is rock solid for me. 
I set my MIDI buffer at over 1,000. The scarlett I use a medium buffer setting of 7. 

I have latest drivers, downloaded few minutes ago from focusrite webpage. The keyboard is plugged in the 6i6. 
here are some pictures from "Preferences"




Is it OK? 

So I assume your Keyboard is not USB as it does not show on the list and you are using the midi port. 
One thing that's a very low buffer setting, on my system I would experience drop outs at that low a setting. 
While trouble shooting I would open Mix Control and set the buffer in the middle. 
 
Un check the Microsoft Wavetable in midi outputs and choose nothing if your not using your midi output. This will allow Sonar to automatically load TTS-1 when you open a MIDI file and saves time. 
 
I see nothing else that would explain midi latency. Possibly a setting in the keyboard itself? 

Oh I just noticed you need to up your MIDI Buffers 250 is way too low I use over 1,000. 

Cactus Music
So I assume your Keyboard is not USB as it does not show on the list and you are using the midi port. 
One thing that's a very low buffer setting, on my system I would experience drop outs at that low a setting. 
While trouble shooting I would open Mix Control and set the buffer in the middle. 
 
Un check the Microsoft Wavetable in midi outputs and choose nothing if your not using your midi output. This will allow Sonar to automatically load TTS-1 when you open a MIDI file and saves time. 
 
I see nothing else that would explain midi latency. Possibly a setting in the keyboard itself? 

I unchecked ms wavetable, but now I can't hear anything from that