It looks like there has been a number of test runs with some random transient network failures on Soraka, causing test dependency downloads to fail:

https://stainless.corp.google.com/search?view=list&build=R73&test=video_PowerConsumption.hw_hangout.vp8&board=%5Esoraka%24&first_date=2018-11-20&last_date=2018-12-18&status=GOOD&status=WARN&status=FAIL&status=ERROR

Could someone check what's going on?