I am useing IMAP Gmail and now after few days it's shows me Failure communication with remote server. How ever I can see all my mail and it works well.

What should I do?

Exception:

com.zimbra.common.service.ServiceException: system failure: Synchronization of folder '/[Gmail]/Kaikki viestit' failed
ExceptionId:btpool0-9:1259087615220:4523a761a46c2c5b
Code:service.FAILURE
at com.zimbra.common.service.ServiceException.FAILURE (ServiceException.java:253)
at com.zimbra.cs.datasource.ImapSync.syncFailed(ImapS ync.java:298)
at com.zimbra.cs.datasource.ImapSync.syncMessages(Ima pSync.java:260)
at com.zimbra.cs.datasource.ImapSync.syncFolders(Imap Sync.java:195)
at com.zimbra.cs.datasource.ImapSync.importData(ImapS ync.java:152)
at com.zimbra.cs.offline.OfflineImport.importData(Off lineImport.java:88)
at com.zimbra.cs.offline.GMailImport.importData(GMail Import.java:52)
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.service.offline.OfflineSync.handle(O fflineSync.java:49)
at com.zimbra.soap.SoapEngine.dispatchRequest(SoapEng ine.java:429)
at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.jav a:286)
at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.jav a:160)
at com.zimbra.soap.SoapServlet.doPost(SoapServlet.jav a:275)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:727)
at com.zimbra.cs.servlet.ZimbraServlet.service(Zimbra Servlet.java:187)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(Ser vletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler.handle(Se rvletHandler.java:362)
at org.mortbay.jetty.security.SecurityHandler.handle( SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(Se ssionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(Co ntextHandler.java:716)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebA ppContext.java:406)
at org.mortbay.jetty.handler.ContextHandlerCollection .handle(ContextHandlerCollection.java:211)
at org.mortbay.jetty.handler.HandlerCollection.handle (HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(Ha ndlerWrapper.java:139)
at org.mortbay.jetty.handler.RewriteHandler.handle(Re writeHandler.java:176)
at org.mortbay.jetty.handler.HandlerWrapper.handle(Ha ndlerWrapper.java:139)
at org.mortbay.jetty.Server.handle(Server.java:313)
at org.mortbay.jetty.HttpConnection.handleRequest(Htt pConnection.java:506)
at org.mortbay.jetty.HttpConnection$RequestHandler.co ntent(HttpConnection.java:844)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser. java:644)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpPa rser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnec tion.java:381)
at org.mortbay.io.nio.SelectChannelEndPoint.run(Selec tChannelEndPoint.java:396)
at org.mortbay.thread.BoundedThreadPool$PoolThread.ru n(BoundedThreadPool.java:442)
Caused by: com.zimbra.common.service.ServiceException: system failure: Unable to store IMAP message data
ExceptionId:btpool0-9:1259087615213:4523a761a46c2c5b
Code:service.FAILURE
at com.zimbra.common.service.ServiceException.FAILURE (ServiceException.java:253)
at com.zimbra.cs.db.DbImapMessage.storeImapMessage(Db ImapMessage.java:69)
at com.zimbra.cs.datasource.ImapFolderSync.moveMessag e(ImapFolderSync.java:1128)
at com.zimbra.cs.datasource.ImapFolderSync.moveMessag es(ImapFolderSync.java:1069)
at com.zimbra.cs.datasource.ImapFolderSync.syncMessag es(ImapFolderSync.java:232)
at com.zimbra.cs.datasource.ImapSync.syncMessages(Ima pSync.java:257)
... 35 more
Caused by: java.sql.SQLException: The statement was aborted because it would have caused a duplicate key value in a unique or primary key constraint or unique index identified by 'I_UID_IMAP_ID' defined on 'IMAP_MESSAGE'.
at org.apache.derby.impl.jdbc.SQLExceptionFactory.get SQLException(Unknown Source)
at org.apache.derby.impl.jdbc.Util.generateCsSQLExcep tion(Unknown Source)
at org.apache.derby.impl.jdbc.TransactionResourceImpl .wrapInSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.TransactionResourceImpl .handleException(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedConnection.handleE xception(Unknown Source)
at org.apache.derby.impl.jdbc.ConnectionChild.handleE xception(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedStatement.executeS tatement(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedPreparedStatement. executeStatement(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedPreparedStatement. executeUpdate(Unknown Source)
at org.apache.commons.dbcp.DelegatingPreparedStatemen t.executeUpdate(DelegatingPreparedStatement.java:2 33)
at com.zimbra.cs.db.DbImapMessage.storeImapMessage(Db ImapMessage.java:66)
... 39 more
Caused by: ERROR 23505: The statement was aborted because it would have caused a duplicate key value in a unique or primary key constraint or unique index identified by 'I_UID_IMAP_ID' defined on 'IMAP_MESSAGE'.
at org.apache.derby.iapi.error.StandardException.newE xception(Unknown Source)
at org.apache.derby.impl.sql.execute.IndexChanger.ins ertAndCheckDups(Unknown Source)
at org.apache.derby.impl.sql.execute.IndexChanger.doI nsert(Unknown Source)
at org.apache.derby.impl.sql.execute.IndexChanger.ins ert(Unknown Source)
at org.apache.derby.impl.sql.execute.IndexSetChanger. insert(Unknown Source)
at org.apache.derby.impl.sql.execute.RowChangerImpl.i nsertRow(Unknown Source)
at org.apache.derby.impl.sql.execute.InsertResultSet. normalInsertCore(Unknown Source)
at org.apache.derby.impl.sql.execute.InsertResultSet. open(Unknown Source)
at org.apache.derby.impl.sql.GenericPreparedStatement .execute(Unknown Source)
... 44 more