Our users in the office check mails using a number of different email clients, including webmail. However, when using KDE's Kmail, we regularly (as in almost each click in the IMAP folder structure), we see a pop-up error message like this:

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Error while uploading status of messages to server:

Cannot Write to Resource
This means that although the resource, Changing the flags of message imap://user%40domain.com@zimbra.emailserver.domain.com:14 3/Junk/;UID=1039 failed., was able to be opened, an error occurred while writing to the resource.

Details of the request:
URL: (unknown)
Date and time: Saturday 18 November 2006 09:33
Additional information: Changing the flags of message imap://user%40domain.com@zimbra.emailserver.domain.com:14 3/Junk/;UID=1039 failed.

Possible causes:
You may not have permissions to write to the resource.
There may have been a problem with your network connection.
Although unlikely, a hardware error may have occurred.

Possible solutions:
Check your access permissions on this resource.
Check your network connection status.
Contact your appropriate computer support system, whether the system administrator, or technical support group for further assistance.

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* Please note that the email address and domain above has been changed to protect the guilty.

This currently only happens in Kmail and not in any other client (we're using a mix of Thunderbird, Outlook and Evolution in addition to Kmail).

When the above error message happens on the email client, an exception similar to the following is logged in zimbra.log:

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2006-11-18 09:41:03,628 WARN [ImapServer-47] [ip=202.190.62.1;name=user@domain.com;] imap - UID STORE failed
com.zimbra.cs.mailbox.MailServiceException: cannot apply tag "\Draft" to item 1052
at com.zimbra.cs.mailbox.MailServiceException.CANNOT_ TAG(MailServiceException.java:250)
at com.zimbra.cs.mailbox.Mailbox.alterTag(Mailbox.jav a:3549)
at com.zimbra.cs.operation.AlterTagOperation.callback (AlterTagOperation.java:86)
at com.zimbra.cs.operation.Operation.schedule(Operati on.java:190)
at com.zimbra.cs.imap.ImapHandler.doSTORE(ImapHandler .java:1773)
at com.zimbra.cs.imap.ImapHandler.executeRequest(Imap Handler.java:470)
at com.zimbra.cs.imap.ImapHandler.processCommand(Imap Handler.java:227)
at com.zimbra.cs.tcpserver.ProtocolHandler.processCon nection(ProtocolHandler.java:231)
at com.zimbra.cs.tcpserver.ProtocolHandler.run(Protoc olHandler.java:198)
at EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Wo rker.run(Unknown Source)
at java.lang.Thread.run(Thread.java:595)

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The email client is configured as follows:
1) IMAP access (have not tested with POP as the KMail users access using IMAP exclusively)
2) Connection is protected via TLS

If there are any pointers as to how to solve this, I would appreciate it.

Thank you!!
Wong