Thanks for reaching out to the Community.
We're sorry to hear you're having trouble with your Google Home devices. We recommend that each user uses the log out everywhere feature on their account pages and then disconnects the account from Google Home. You can learn how to do this here.
Afterwards perform a clean reinstall of both the Google Home and Spotify apps. You can find a detailed guide on how to do this for Spotify here. Give your device a restart before opening the newly installed apps and connect the accounts anew. This page can help, plus has some useful general tips on Spotify and Google Home devices.
Hope you find this helpful. Keep us posted how you get on.
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