Are you trying to share your calendar or looking at a calendar someone shared with you? You can't change the permissions on another's calendar so have no need for that tab.
I'm trying to share somebody else's calendar, but am trying to do it from their machine on their outlook account. I was able to do it on other accounts, but it seems that for this one, the security tab just isn't available.
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NATHAN WELDON
Are you trying to share your calendar or looking at a calendar someone shared with you? You can't change the permissions on another's calendar so have no need for that tab.