Where are you clicking the link from? Are you testing it in "preview" or have you sent yourself a test? I get a similar message when I click it via preview, so you do have to send yourself a test and then you should see the link.
Thanks for responding, I sent an invite to myself from Marketo that has the "Save the Date" link, so I clicked that to add it to my Outlook calendar. When I click the link in the Outlook calendar is when it says webpage cannot be displayed.
This is an old thread - but I am having similar problems with trying to add an ics file/ save the date link. it works sometimes and not others.
The last two user meetings we've been to, they say this still isn't working properly.