MTA is able to process all mailboxes except one, the error is: MAPI_E_LOGON_FAILED (4349088)

Mail Target Agent fails with an error:

"CSession::Logon Error -2147221231 The information store could not be opened. - MAPI_E_LOGON_FAILED (MAPI 1.0) Low level error: 0x0 File: 'aeWrapHelpers.h' Line: '279'"

When using Outlook and when using MFCMAPI the mailbox can be opened, even when using the LEDN - /O=ABC/OU=XYZ/cn=Recipients/cn=Bob

The entries in the log file are:
8/12/2008 7:17:02 AM CMBMConn::GetMailboxInfoEx TraceMsg 4808 Retrieving mailbox information (Mailbox: '/O=ABC/OU=XYZ/cn=Recipients/cn=Bob ', Infostore: 'E7C6CFCDC0595A429E6C9792926AFBC2').
8/12/2008 7:17:02 AM PSTFile::InfoBackup TraceMsg 1614 Backing up the auxiliary information for current PST file container 'C:\WINDOWS\system32\Aelita Exchange Migration Wizard\Mail Source Agent\PST\6FE7B016425AD646A72C80A19C610246.PRV'.
8/12/2008 7:17:02 AM CSession::Logon TraceMsg 4800 Logging on to the mailbox '/O=ABC/OU=XYZ/cn=Recipients/cn=Bob ' (Server: 'SERVERNAME', user: 'Domain\serviceaccount').
8/12/2008 7:17:02 AM CSession::Logon Error -2147221231 The information store could not be opened. - MAPI_E_LOGON_FAILED (MAPI 1.0) Low level error: 0x0 File: 'aeWrapHelpers.h' Line: '279'
8/12/2008 7:17:02 AM MailKernel::Connect Informational 2079 Synchronization status: Object '/O=ABC/OU=XYZ/cn=Recipients/cn=Bob ' synchronization was not started due to connection errors.
8/12/2008 7:17:02 AM MailKernel::Disconnect TraceMsg 2042 Total errors occured during processing 1; internal errors 0; warnings 0.
8/12/2008 7:17:02 AM MailKernel::Work TraceMsg 2061 Synchronization has been completed. (RetCode: -2147221502).
8/12/2008 7:17:02 AM PSTFile::Delete TraceMsg 1613 Deleting the file 'C:\WINDOWS\system32\Aelita Exchange Migration Wizard\Mail Source Agent\PST\6FE7B016425AD646A72C80A19C610246.PRV'.