When one of our users sends a meeting request, the person accepting it gets
an undeliverable back saying the following recipient: ADCDisabledMail.  I
realize this can be the value of the legacyexchangedn attribute in AD, but
how has it got confused with being a recipient on a meeting request
acceptance?

Out of Office Assistant Not Working Outlook2002/Exchange 5.5
the message can not be deliverd because of a configuration error
Exchange showing odd SMTP domains in queue
Forwarding a copy of an email to an alternate address
OWA logon page - changes