Due to some confusion with Israeli vs. Diaspora sedra schemes, I have modified the user interface on the Interactive Calendar page to make the option easier to use. Instead of a checkbox, it’s now displayed as a radio button (a choice between the two options).
You should select the appropriate option depending on where you live (Israeli sedra scheme for those living inside Israel, Diaspora for everyone else).
I have also fixed the 1-Click Shabbat service (both web and email versions) to automatically select Israeli sedra scheme for cities in Israel.