Welcome @goodwillhinton !
Thanks for sharing that you’re having the same experience.
I left one of my test sheets open over night with the add-on also open in the spreadsheet and this morning it’s showing the “sign in to Tiller” page rather than having loaded the sidebar.
If I click “sign in to Tiller” and try to sign in I see the “The state token is invalid or has expired. Please try again.” message.
If I launch my personal Tiller sheet from the Console and launch the add-on it does not prompt me to sign in (the token in has persisted).
So I think this is actually isolated to if you’re leaving the sheet and add-on open and is likely a Google security/protection type of thing moreso than anything we changed.
So the recommendation here is to just close out your sheet or at least close out the add-on 