New-MailboxExportRequest: Couldn’t Connect to the Source Mailbox
When you run this cmdlet:
New-MailboxExportRequest <username> -FilePath \\servername\sharename\username.pst
…and you get this error message:
Couldn’t connect to the source mailbox.
+ CategoryInfo : NotSpecified: (0:Int32) [New-MailboxExportRequest], RemotePermanentException
+ FullyQualifiedErrorId : B1C4188,Microsoft.Exchange.Management.RecipientTasks.NewMailboxExportRequest
…the most common problem is that the source mailbox has been hidden from the GAL. Oddly, it doesn’t happen with every mailbox that is hidden. It is probably a combination of factors, such as hidden + litigation hold.
Unhide the mailbox and try the export again.