Failed to authenticate with Google
I had this same issue now, I think. I had updated the password for my gmail account and needed to re-authenticate the Google account in Mac OS. When I went into System Preferences > Internet Accounts I got a dialog saying I needed to re-authenticate and when I clicked the "Open Safari" button in the dialog I just got an error message saying Failed to authenticate with Google.

Solution was to restart my computer, after that it worked just fine.

(I also set my default browser to Safari as recommended on reddit but that didn't help before the restart so I don't think it helped at all)