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An ActiveData (activedatax.com) ICS feed which is valid according to iCalendar Validator is invalid according to Zimbra webmail when I try to subscribe to an external feed: http://209.87.161.197/CalendarNOW.aspx (forward DNS entry missing).
Has anyone had success subscribing to ActiveData ICS files with Zimbra?
I see the error described above with Zimbra 5.18. I've been told by someone running Zimbra 5.19 that they are able to import the ICS file but that "there's no subject, location, or details accompanying any of the events".
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Zimbra invalid ICS, from ActiveData calendar 
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