Receive mail fine. Get error when trying to send mail. Comes up with an error as below:

Debug message: Yahoo address book synchronization failed

Exception:

com.zimbra.cs.offline.ab.yab.YabImport$1: Yahoo address book synchronization failed
ExceptionId:mid=4:1331245947757:f81b6682cfdea441
Code:yab.999
at com.zimbra.cs.offline.ab.yab.YabImport.serviceExce ption(YabImport.java:98)
at com.zimbra.cs.offline.ab.yab.YabImport.failed(YabI mport.java:84)
at com.zimbra.cs.offline.ab.yab.YabImport.importData( YabImport.java:72)
at com.zimbra.cs.offline.OfflineImport.importData(Off lineImport.java:88)
at com.zimbra.cs.offline.YMailImport.importData(YMail Import.java:59)
at com.zimbra.cs.datasource.DataSourceManager.importD ata(DataSourceManager.java:157)
at com.zimbra.cs.mailbox.LocalMailbox.importData(Loca lMailbox.java:417)
at com.zimbra.cs.mailbox.LocalMailbox.syncAllLocalDat aSources(LocalMailbox.java:389)
at com.zimbra.cs.mailbox.LocalMailbox.sync(LocalMailb ox.java:431)
at com.zimbra.cs.mailbox.LocalMailbox.syncOnTimer(Loc alMailbox.java:361)
at com.zimbra.cs.mailbox.DesktopMailbox$1.run(Desktop Mailbox.java:437)
at java.util.TimerThread.mainLoop(Unknown Source)
at java.util.TimerThread.run(Unknown Source)