Best answer by Keith N
For example, my Spotify account is set up to my home Sonos. Additionally, I use my Spotify account while at work. If my girlfriend were to not pay attention to the account selected in Sonos and play from my account, it would kick me off Spotify at work giving me a similar message. If I restart playback at work, she would then receive a message just as you did on Sonos.
To read more information about multiple accounts, check out this article.