This was the problem with getting the Nest smoke alarm installed. Crappy uninformative error messages after taking a minute every time to fail. Unfortunately for some reason many smart home vendors make their products more ‘friendly’ and ‘professional’ for us simple home consumer types by making their products devoid of any meaningful log messages when then fail.
I went through the installation process about 10 times before I decided to go buy a high end third party router from Amplifi. That didn’t fix it. Arrrgh. Finally after googling it and taking some time I figured out that the Nest Smoke alarm isn’t smart enough to distinguish a high GHz wifi network from the old low GHz wifi network and because the router from Teksavvy (which I think they got from Rogers) was installed with trying to pretend that the two networks were the same and gave them the same SSID.