I was getting the exact same errors. I battled this issue for a few hours today. It seemed to be caused by a mismatch between the versions of chromedriver and selenium-server-standalone. The config.js file was referencing a directory that had chromedriver 2.9 and selenium-server-standalone 2.35.0. Once I made sure we were referencing 2.10 and 2.42.2, it worked.