Can't play tts, mp3, mp4 on Nest Hub from HA; Nest hub responds, doesnt' play anything

Hoping for some insight: One day it just stopped, don’t remember when, around New Year. My Nest Hubs will no longer play any messages or videos from HA. I can cast to them from other devices fine. The Nest hubs will respond when they’re supposed to with either a blank screen or “Media Default Player Message” but they will never play the tts or video they used to play.
I even created an entirely new version of HA to see if that would help…same result. The Nest hubs respond, they simply won’t play the messages.
Any ideas? Would really like to have this function back. Thanks in advance.