I turned on the "Debug Logging"
Here is the contents of the log file, it is only part of the file, hope this is sufficient.
thanks
2008-12-24 00:01:50,818 INFO [mid=4] [] offline - >>>>>>>> 008-12-24 00:01:50,825 INFO [mid=4] []
datasource - Importing data for data source 'My Yahoo'
2008-12-24 00:01:51,283 INFO [mid=4] [] datasource - Importing contacts for YMail account 'My Yahoo'
2008-12-24 00:01:51,294 DEBUG [mid=4] [] yab - Loaded sync state for data source 'My Yahoo':
{lastModSequence=11499, lastRevision=8}
2008-12-24 00:01:51,296 DEBUG [mid=4] [] yab - found 0 local contact changes
2008-12-24 00:01:51,806 DEBUG [mid=4] [] yab - Sending request: GET
http://address.yahooapis.com/v1/sync...SJkrfBlr3wgxc-
&WSSID=72iekHFHM8B&format=xml&myrev=8
2008-12-24 00:01:52,012 INFO [mid=4] [] datasource - Import completed for data source 'My Yahoo'
2008-12-24 00:01:52,013 ERROR [mid=4] [] offline - sync failure: My Yahoo
com.zimbra.common.service.ServiceException: system failure: Yahoo address book synchronization failed
ExceptionId:mid=4:1230094912012:0a4f6030d0bc5e21
Code:service.FAILURE
at com.zimbra.common.service.ServiceException.FAILURE (ServiceException.java:253)
at com.zimbra.cs.mailbox.SyncExceptionHandler.checkRe coverableException
(SyncExceptionHandler.java:39)
at com.zimbra.cs.offline.ab.yab.YabImport.importData( YabImport.java:59)
at com.zimbra.cs.offline.YMailImport.importData(YMail Import.java:59)
at com.zimbra.cs.datasource.DataSourceManager.importD ata(DataSourceManager.java:154)
at com.zimbra.cs.mailbox.LocalMailbox.importData(Loca lMailbox.java:367)
at com.zimbra.cs.mailbox.LocalMailbox.syncAllLocalDat aSources(LocalMailbox.java:340)
at com.zimbra.cs.mailbox.LocalMailbox.sync(LocalMailb ox.java:401)
at com.zimbra.cs.mailbox.LocalMailbox.syncOnTimer(Loc alMailbox.java:312)
at com.zimbra.cs.mailbox.DesktopMailbox$1.run(Desktop Mailbox.java:262)
at java.util.TimerThread.mainLoop(Unknown Source)
at java.util.TimerThread.run(Unknown Source)
Caused by: com.zimbra.common.service.ServiceException: system failure: Contact sync error
ExceptionId:mid=4:1230094912012:0a4f6030d0bc5e21
Code:service.FAILURE
at com.zimbra.common.service.ServiceException.FAILURE (ServiceException.java:253)
at com.zimbra.cs.offline.ab.yab.SyncSession.sync(Sync Session.java:87)
at com.zimbra.cs.offline.ab.yab.YabImport.importData( YabImport.java:57)
... 9 more
Caused by: org.apache.commons.httpclient.HttpException: HTTP request failed: 999: null
at com.zimbra.cs.offline.util.yab.Request.sendRequest (Request.java:77)
at com.zimbra.cs.offline.util.yab.Request.send(Reques t.java:52)
at com.zimbra.cs.offline.util.yab.SyncRequest.send(Sy ncRequest.java:79)
at com.zimbra.cs.offline.ab.yab.SyncSession.syncData( SyncSession.java:102)
at com.zimbra.cs.offline.ab.yab.SyncSession.sync(Sync Session.java:85)
... 10 more
2008-12-24 00:05:40,574 INFO [mid=5] [] offline - >>>>>>>>
name=xxxxxxx@yahoo.com;version=0.92;build=1418;rel ease=BETA;os=Windows Vista x86 6.0;type=imap
2008-12-24 00:05:40,576 INFO [mid=5] [] datasource - Importing data for data source 'Yahoo Mail'
2008-12-24 00:05:40,948 INFO [mid=5] [] datasource - Importing contacts for YMail account 'Yahoo Mail'
2008-12-24 00:05:40,959 DEBUG [mid=5] [] yab - Loaded sync state for data source 'Yahoo Mail':
{lastModSequence=17599, lastRevision=129}
2008-12-24 00:05:40,964 DEBUG [mid=5] [] yab - found 0 local contact changes
2008-12-24 00:05:41,345 DEBUG [mid=5] [] yab - Sending request: GET
http://address.yahooapis.com/v1/sync...SJkrfBlr3wgxc-
&WSSID=g.XJ/SOLGY7&format=xml&myrev=129
2008-12-24 00:05:42,171 INFO [mid=5] [] datasource - Import completed for data source 'Yahoo Mail'
2008-12-24 00:05:42,173 ERROR [mid=5] [] offline - sync failure: Yahoo Mail
com.zimbra.common.service.ServiceException: system failure: Yahoo address book synchronization failed
ExceptionId:mid=5:1230095142171:0a4f6030d0bc5e21
Code:service.FAILURE
at com.zimbra.common.service.ServiceException.FAILURE (ServiceException.java:253)
at com.zimbra.cs.mailbox.SyncExceptionHandler.checkRe coverableException
(SyncExceptionHandler.java:39)
at com.zimbra.cs.offline.ab.yab.YabImport.importData( YabImport.java:59)
at com.zimbra.cs.offline.YMailImport.importData(YMail Import.java:59)
at com.zimbra.cs.datasource.DataSourceManager.importD ata(DataSourceManager.java:154)
at com.zimbra.cs.mailbox.LocalMailbox.importData(Loca lMailbox.java:367)
at com.zimbra.cs.mailbox.LocalMailbox.syncAllLocalDat aSources(LocalMailbox.java:340)
at com.zimbra.cs.mailbox.LocalMailbox.sync(LocalMailb ox.java:401)
at com.zimbra.cs.mailbox.LocalMailbox.syncOnTimer(Loc alMailbox.java:312)
at com.zimbra.cs.mailbox.DesktopMailbox$1.run(Desktop Mailbox.java:262)
at java.util.TimerThread.mainLoop(Unknown Source)
at java.util.TimerThread.run(Unknown Source)
Caused by: com.zimbra.common.service.ServiceException: system failure: Contact sync error
ExceptionId:mid=5:1230095142171:0a4f6030d0bc5e21
Code:service.FAILURE
at com.zimbra.common.service.ServiceException.FAILURE (ServiceException.java:253)
at com.zimbra.cs.offline.ab.yab.SyncSession.sync(Sync Session.java:87)
at com.zimbra.cs.offline.ab.yab.YabImport.importData( YabImport.java:57)
... 9 more
Caused by: org.apache.commons.httpclient.HttpException: HTTP request failed: 999: null
at com.zimbra.cs.offline.util.yab.Request.sendRequest (Request.java:77)
at com.zimbra.cs.offline.util.yab.Request.send(Reques t.java:52)
at com.zimbra.cs.offline.util.yab.SyncRequest.send(Sy ncRequest.java:79)
at com.zimbra.cs.offline.ab.yab.SyncSession.syncData( SyncSession.java:102)
at com.zimbra.cs.offline.ab.yab.SyncSession.sync(Sync Session.java:85)
... 10 more