Did you by any chance change your Wi-Fi settings and are now trying to reconnect/re-install your cameras?
If so, and you did not first remove your cameras from your Google Nest app or Google Home app while still on the old Wi-Fi network, you can get the message saying your cameras are connected to another account (even though it is YOUR account it is connected to), because the cameras still have the old Wi-Fi settings in them.
Are you signing onto the Google Nest app or the Google Home app with the same Google account you were using previously? Or with the Nest Account if you have an old, unmigrated Nest Account?
Otherwise, Google Nest's process for changing control of Google Nest devices is cumbersome. The previous owner needs to remove the devices from their Google Nest app or Google Home app while connected to the Wi-Fi network where they are currently assigned. Then they have to be factory reset, which in most cases requires physical access to the devices. Then they have to be re-installed on the new owner's Google Nest app or Google Home app.
I figured out after many wasted hours of trying that this is related to that migration. It didn’t work. That is what happened. Over and over of trying to get my account or devices to migrate. I am forced into a migration that failed over and over and wasted my valuable time. I am NEVER buying Google products again after this. I see the cameras now after wasting more than a day. I had put them in the back of my car to take to the electronics dump, and then I look and see in Google Home app, that they suddenly show up after many failed attempts. NOT WORTH IT. A WASTE OF MY TIME. Their directions and migration have obviously caused consumers issues, which one can see by looking at Amazon product reviews of the latest cameras, which by the way, are apparently inferior to the original NestCams, as is this stupid Google Home app.
If your older Google Nest cameras now appear in the Google Home app after your migration finally worked, they should also still appear in the Google Nest app (as long as you're signing onto both apps with the same Google account). For our older cameras, Google Nest still handles notifications and administration in the Google Nest app.
For our older cameras, Google Nest has us halfway between the two apps. They say they're working on bringing things together, but progress is slow.
Several weeks ago, Google Nest made available a "preview' version of a live-streaming website, https://home.google.com. At present, it's just live-streaming, and does not have the functionality of the https://home.nest.com for our older Google Nest cameras.
FYI, it may not address your concerns, but Google Nest has also announced an upcoming upgrade of the Google Home app:
Thank you for that. I can’t control the cameras anymore in the Next app. I tried logging out and in, logging out and in, over and over, trying my two Google accounts and even the Yahoo email and it doesn’t work. I don’t know what they are doing, but they are going to lose some customers if they keep this up, with so little help or explanation that I have to come begging here after wasting hours of my life this weekend that I won’t get back.
Thank you for your feedback on this, I fully understand the frustrations of not having your new Nest cams in the Nest app like you may be used too. However, you can now use the Google Home web app to view your cameras and doorbells.
The new Nest cameras and doorbell are exclusive to the home app because we wanted to create an integrated experience with your speakers and displays. A Nest Aware subscription applies to all of your cameras, speakers, and displays in the same home structure. Thank you for your continued patience, and support.
Just checking in to make sure that you've seen our responses. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.
I appreciate the help, Brad.