Same issue... brand new and periodically, I receive an error that live video is not available. I remove the doorbell from the mount, plug it back in, (sometimes) restart my Google Nest Mesh WiFi and it all works. Would be nice if there was a restart option, like there is on the Mesh WiFi points.
I apologize for my late response and thank you for all of your patience while waiting for a reply. I can definitely understand how frustrating your situation must be, but I wanted to make sure that your issue was addressed. Do you still need help with this issue? I know that there's been a delay in response since you posted.
Please let me know if you need further assistance.