Pavlovia errors - stimuli on different screen and experiment ended halfway

URL of experiment: Illusions [PsychoPy]

Description of the problem:

Hi, I am already running my final year project and data collection. I was confident it worked well because when we tested among 4 researchers (different computer screens), it worked fine with no problems except when using safari and we have included to use google chrome in our study advertisement.

My problem is

  1. 2 participants encountered that our horizontal line in the 2nd type of illusion (horizontal-vertical) is too close to the computer screen and not visible.
    The participants were using 14inch and 17inch size computer. I tested the experiment on my 11inch screen and it worked well.

Pic from when I ran the experiment on 11inch
Although it was too close but it was still visible unlike for the affected participants

  1. Halfway through the experiment (middle of first type of illusion), participant said the session ended.

What could be the factors for these?