Button click N-back task

What are you trying to achieve?:
I am trying to do a 1-back task where participants need to click the button ‘same’ or ‘not same’ whether the letter presented before was identical to the current letter. I included the button option because the task needs to be administered on a phone so the key response option is not possible.

What did you try to make it work?:

Each button is set for every repeat, and the mouse has clickable stimuli for the buttons (see screenshot). I also wanted to add a feedback to the clicking, so participants see which option they clicked.


What specifically went wrong when you tried that?:
When I run the experiment, I get the first letter appearing on the screen and the two button options but when I click, nothing happens the experiment gets ‘frozen’ with displaying the buttons but not be able to move forward anymore.

Maybe there is an easier option to track responses than the button option, I just wasn’t sure what to use when I want to make it applicable to the phone.