If you're using Logic Pro as your DAW and finding that when you stop playback the Dynamics control in your libraries gets reset to a value of 0 (resulting in soft or no sound when playing on your MIDI keyboard) then see the settings below.
First you should try the "No Reset" option in the Track panel. This will stop Logic from sending reset messages to the plugin when playback is paused, and is independent of the global parameters for this.
If that doesn't resolve your issue, then you should next check the global settings under Settings > MIDI > Reset Messages and ensure that the "Control 1 (Modulation) to zero" option is unchecked.
If you're still unable to stop the controllers from resetting, please get in touch with us using the support widget in the bottom right corner of this page.