Some Akai Pro consoles and controllers have CV/Gate outputs which are designed to deliver approximately 5V using standard 1/8” (3.5 mm) TS cables.
To verify if the signal is properly transmitted from the CV/Gate outputs to your external synth, you can use a multimeter.
Whilst holding down a pad or key on your Akai Pro device, place the positive (red) probe of the multimeter on the tip of the TS cable's jack connector, and the negative (black) probe on the sleeve.
If the multimeter's screen does not display a number which is close to 5V, please ensure that your product is connected directly to a wall socket without any extensions or hubs in the middle of the connction, and swap out your CV/Gate cables, ensuring that a TS jack is used.
To learn how to best utilize CV/Gate outputs, please see our support video: Akai Pro MPK Mini Plus | How to Use the CV & Clock Outputs (youtube.com)