Unable to subscribe to published calendar in Outlook 2010

More Outlook 2010 troubles. I re-created an Outlook Account for a user, then WebDAV published his calendar. I then sent out an invitation to another Outlook user in the office to subscribe to his calendar.

When she does so, either by clicking on the email icon, or clicking on the link webcals://webdavserver.org/calendars/Mark_Atkeson_Calendar.ics, the calendar shows, sort of, but no events are shown (the same "Eric Short" event should also be on this calendar), and the calendar name is not listed in the left-column with the other shared calendars. If Outlooks is closed and reopened, the name appears, un-checked, in the list of Shared Calendars at left, but as soon as it is checked the entry disappears.

At the same time, Thunderbird users subscribed to this same calendar have no problem and do see this person's events.

This question was published 8 days ago with no response. I don't find an "ask for help" button any more. I'll give this a couple of more days, then remove it.

After further investigate I've found that I cannot deleted the calendar from the subscriber's calendar list. I right-click it, select delete, and it goes away. But as soon as a restart Outlook it's back. First mission: how can I deleted this subscription?

Any idea what's going on and how to fix?
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