Botium Test Suddenly Stopped

I used Botium to test our chatbot. But in the middle of the process, the test suddenly stopped.

Not sure why "Stop called" even though my test haven't finished yet. This is what I got by running with --verbose.

2019-02-26T07:42:23.973Z botium-Convo Library Test wait for bot null
2019-02-26T07:42:24.202Z botium-connector-webdriverio Found new bot response element .vcw-message-container, id 0.9475738262354745-147
CHECKING ELEMENT 0.9475738262354745-147
2019-02-26T07:42:24.203Z botium-connector-webdriverio polling for bot output (.vcw-message-container)
FROM ME DECIDED 0.9475738262354745-147
no images: 0.9475738262354745-147
no audio: 0.9475738262354745-147
no video: 0.9475738262354745-147
    1) Library Test
2019-02-26T07:42:25.230Z botium-connector-webdriverio Stop called
2019-02-26T07:42:25.288Z botium-connector-webdriverio Clean called
2019-02-26T07:42:25.289Z botium-BaseContainer Cleanup rimrafing temp dir /var/lib/jenkins/workspace/botium-widget-prodtest/botiumwork/Production-Test-20190226-144119-7H0sV


  0 passing (1m)
  1 failing