Try posting this to an Exchange list - they might know more about Exchange
and sites than us.

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Milly Staples [MVP - Outlook]
Post all replies to the group to keep the discussion intact. All
unsolicited mail sent to my personal account will be deleted without
reading.
After furious head scratching, Darrin asked:
| Created a calendar in all public folders in site1
| Gave permission to 10 users total (7 from site1 and 3 from site2)
[quoted text clipped - 12 lines]
| servicing this public folder is down or the public folder has not
| been replicated to this site. See your administrator.