Unable to run Selenium tests on CentOS through Xvfb - selenium

Question

I'm running Selenium tests on CentOS 7 machine through Jenkins pipeline hence using Xvfb. When use screen argument with any valid value like following -
wrap([$class: 'Xvfb', autoDisplayName: true, screen: '1440x800x8']) {
<code to run Selenium test here>
}
It results into following error -
[testng] org.openqa.selenium.WebDriverException: chrome not reachable
[testng] (Session info: chrome=80.0.3987.132)
[testng] (Driver info: chromedriver=80.0.3987.16 (320f6526c1632ad4f205ebce69b99a062ed78647-refs/branch-heads/3987#{#185}),platform=Linux 3.10.0-862.el7.x86_64 x86_64) (WARNING: The server did not provide any stacktrace information)
[testng] Command duration or timeout: 0 milliseconds
[testng] Build info: version: '3.14.0', revision: 'aacccce0', time: '2018-08-02T20:13:22.693Z'
If we run it without screen argument it runs successfully.
One more observation - with screen argument, it perfectly works on Ubuntu 18
Please help me how I can run Selenium tests with screen argument on CentOS 7.

Answer 1

After trying with different values for screen parameters, I realized this is not something which is wrong with Chrome browser or driver but with value passed to screen
When I changed depth value from 8 to 16, Selenium execution started successfully - screen: '1440x800x16'
wrap([$class: 'Xvfb', autoDisplayName: true, screen: '1440x800x16']) {
<code to run Selenium test here>
}
But technically, I did not understand why this error occurs and how depth value helped to resolve it.