If you install Mailbox Manager on one server in a site and use it to clean mailboxes on another server in the site, the following error message is logged in the application event log:
Event ID: 1023
Source: MSExchangeIS Private
Type: Failure Audit
Category: Logons
Description:
Domain\ServiceAccount was validated as
/o=Organization/ou=Site/cn=Configuration/cn=Add-Ins/cn=
MCAServerName but was unable to log on to
/o=Organization/ou=Site/cn=Recipients/cn=userA1.
Even though the 1023 error message indicates that the Mailbox Manager was unable to log on to the remote mailbox, the remote mailbox is cleaned. Note that a 1023 error message is logged for each remote mailbox that you clean.