title: Selenium Webdriver - tried to run command without establishing a connection
body: <p>I'm new to selenium webdriver. 
  I wrote a unittest script and ran it on 2 different windows 10 machines.
  On the first machine the code ran without any errors.
  When I run the code on the second machine, the code is executed and I can see that all the tests passed, but I still get the following error:
  "tried to run command without establishing a connection"</p>
  
  <p>What is the reason for this, and how can I resolve this issue?
  Thx</p>