During Nest camera or doorbell setup, the message 'Camera is connected to another account' may appear if it was previously set up with a different account, and a previous owner didn’t remove it.
To transfer the Nest camera or doorbell to your account, you need to ask the previous owner to remove it from their account. The camera or doorbell should be removed from the Nest app or the Google Home app, whichever app it was set up in. Once they remove it, you can set up your device.
If you bought this camera new or can’t get the previous owner to remove the camera from their account, return it to the seller for a refund or exchange it for another. Let the seller know that your product is already connected to someone else’s account and it can’t be set up.