For the record, I think this is a Vudu problem.
https://forum.vudu.com/forum/technical-help/vudu-support-faq/502759-error-unable-to-stream-due-to-network-error
Same issue here. Works fine on Vizio Tv with built in Chromecast
(ethernet). Neither 2nd Gen Chromecasts will play Vudu content right
now. Very frustrating.