Katalon Debian Headless Browser

java selenium jenkins groovy katalon-studio

I think you need to add additional configurations to your Jenkins as well.

Install this plugin: https://wiki.jenkins.io/display/JENKINS/Xvfb+Plugin
After you've installed it, use this settings in 'Additional Settings' field of this plugin:
export DISPLAY=:1.0

For your other issue, can you post the full test case script?