Yosemite Server Backup, version 9.0 and above
When doing Mailbox level backup, if a single mailbox is failing to back up, it could be because MAPI is disabled.
You can test and enable MAPI by using the commands below.
To Test MAPI Connectivity on a single user (replace the domain and user name with the user's being tested):
Test-MapiConnectivity -Identity "domain name\user name"
To turn Enable MAPI on a single user (replace the user name with that being enabled):
Set-CASMailbox -Identity "User Name" -MAPIEnabled $true
Link to this page:https://campus.barracuda.com/solution/501600000013lLFAAY