Public Folders are not synchronizing with Logon Error: "-2147221231 The information store could n (4321985)

Public Folders are  not synchronizing with Error:

21/08/2008 1:29:18 PM 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'
21/08/2008 1:29:18 PM MailKernel::Connect Informational 2079 Synchronization status: Object '/o=Exchange/ou=Administrative Group/cn=Recipients/cn=Pfadmin' synchronization was not started due to connection errors.

Public folder's Administrator mailbox specified on the synchronization job was set to be hidden from the GAL during synchronization.

Unhide public folder's Administrator mailbox from the GAL

How to unhide mailbox from the  GAL
1. Go to Exchange Active Directory User and Computer
2. Properties on the mailbox
3. Click Exchange Advanced tab
4. Make sure "Hide from Exchange address lists" is check box is clear