How can I overcome interruption of COD training?

Hi Matlab community!

I am currently working with a CascadeObjectDetector to detect objects in images.

The training halts after only 2 stages altough my setting is 5 (desirably I like to have more though). Please find below the screenshot of the warning message.

Consequently, my results and object detections are poor but I guess that is expected from a detector trained based on 2 stages only. How can I improve the training process without interruption from occuring?

I have tried multiple times to adjust the parameters as suggested and added many more negative images as well.

My images contain an object of simple shape on a patterned background, where positive samples contain a single object and negative ones the background only.

The problem persists. I would appreciate any leads to solve this problem!

Thanks in advance!

P.S.: I use MATLAB 2019b on MacOS.