I was fighting with my nest mini v2 for days trying to connect it to my wifi. kept getting an error (cannot communicate with nest mini) right after the select wifi screen. I tried everything, Power cycling my phone, the nest and my router. Re-installing the home app. Tried it with three different phones. Even tried a suggested fix of turning my phone to airplane mode and manually turning on wifi and bluetooth.
I finally fixed it by factory resetting the nest mini, which is a solution that nobody suggested anywhere (not even an official google reply to a thread on their help site).
You factory reset it by turning the mic switch to mute, and then holding the middle button on the top of the nest for ten seconds.
Just wanted to share this in case it helps somebody else, cause I could not find this solution anywhere.
Hope this helps someone :D!
I apologize for my late response and thank you for all of your patience while waiting for a reply. I definitely understand how frustrating your situation must be, and I wanted to make sure that your concern was acknowledged. Do you still need help with this issue? I know that there's been a delay in response since you posted.