PLEASE HELP ME , i have error like this :

Product name: Zimbra Desktop
Product version: 7.2.1
Build ID: 11637
Release type: GA
OS Platform: Linux i386 3.5.0-25-generic
Time of event: 2013-06-21 08:58:53
Error type: zclient.IO_ERROR
Item ID: 1
Error summary: Sync failed due to IOException for the following items
Items will be retried on next sync
Item Id: 1073742220 Message: PushChanges.sync


Failure details - PLEASE REMOVE ANY SENSITIVE INFORMATION
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com.zimbra.common.zclient.ZClientException: Connection timed out
ExceptionId:sync-mbox-hendraXXXXXXXXXco.id:1371779931996:6703e6e1affbe8e 4
Code:zclient.IO_ERROR
at com.zimbra.common.zclient.ZClientException.IO_ERRO R(ZClientException.java:45)
at com.zimbra.cs.zclient.ZMailbox.uploadContentAsStre am(ZMailbox.java:1921)
at com.zimbra.cs.mailbox.PushChanges.uploadMessage(Pu shChanges.java:472)
at com.zimbra.cs.mailbox.PushChanges.syncMessage(Push Changes.java:1268)
at com.zimbra.cs.mailbox.PushChanges.sync(PushChanges .java:306)
at com.zimbra.cs.mailbox.PushChanges.sync(PushChanges .java:195)
at com.zimbra.cs.mailbox.MailboxSync.sync(MailboxSync .java:193)
at com.zimbra.cs.mailbox.ZcsMailbox.sync(ZcsMailbox.j ava:124)
at com.zimbra.cs.mailbox.ZcsMailbox.syncOnTimer(ZcsMa ilbox.java:105)
at com.zimbra.cs.mailbox.SyncMailbox$1.run(SyncMailbo x.java:279)
at java.util.TimerThread.mainLoop(Timer.java:512)
at java.util.TimerThread.run(Timer.java:462)
Caused by: java.net.SocketException: Connection timed out
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutp utStream.java:92)
at java.net.SocketOutputStream.write(SocketOutputStre am.java:136)
at java.io.BufferedOutputStream.write(BufferedOutputS tream.java:105)
at org.apache.commons.httpclient.methods.InputStreamR equestEntity.writeRequest(InputStreamRequestEntity .java:171)
at org.apache.commons.httpclient.methods.EntityEnclos ingMethod.writeRequestBody(EntityEnclosingMethod.j ava:499)
at org.apache.commons.httpclient.HttpMethodBase.write Request(HttpMethodBase.java:2114)
at org.apache.commons.httpclient.HttpMethodBase.execu te(HttpMethodBase.java:1096)
at org.apache.commons.httpclient.HttpMethodDirector.e xecuteWithRetry(HttpMethodDirector.java:398)
at org.apache.commons.httpclient.HttpMethodDirector.e xecuteMethod(HttpMethodDirector.java:171)
at org.apache.commons.httpclient.HttpClient.executeMe thod(HttpClient.java:397)
at com.zimbra.common.httpclient.HttpClientUtil.execut eMethod(HttpClientUtil.java:53)
at com.zimbra.common.httpclient.HttpClientUtil.execut eMethod(HttpClientUtil.java:39)
at com.zimbra.cs.zclient.ZMailbox.uploadContentAsStre am(ZMailbox.java:1911)
... 10 more

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I still can send my email, but i always get error this message. How to dissapear this message error.
Please help me, thank you all master Zimbra