I was adding a new battery Nestcam to my already extensive nest estate or protects, a thermostat and other nestcams (20+devices in all). All of the originals were added using the original Nest app, though of course now we are forced to add using the Google home app.
I had immediately hit the 'cannot connect to assisting device' (in my case a protect).
I saw from other threads people are working around the problem by removing/disabling other devices, this really wasn't an option for me as getting rid of all the other devices wasn't feasible.
One thought that did occur to me was that as I have so many devices perhaps I wasn't waking up the Protect that Nest wanted me too, so on the next install attempt I ran around the house with a broomstick and woke up all the Nest protects, sadly this didn't work either.
My next idea (which I progressed with immediately) was to take the Nestcam to the furthest part of my garden away from the house (where I happen to have an outdoor power socket) and I was hoping that if I was out of range of bluetooth the Home app would let me add the camera manually.
Unfortunately it still asked me to wake up a Nest protect - but I couldn't bother to go back to the house and wake one up so I just hit next, and much my surprise it connected to an assisting device and completed the installation!!
My working theory is that one of the nest protects was still awake and the Nestcam was able to connect to it better from garden than through the interior walls of the house.
My further theory is that had I progressively moved around the house room to room I would eventually have found the right nest protect to wake up and completed the installation that way.
I hope that helps someone else.
