I tried to reply to thread 54342, but it does not show up, despite my name shows as the last poster.
So, I try to post a new thread.

Using ZD 7.2.2 GA under Ubuntu 13.10 with one Yahoo acount, two Zimbra account configured as IMAP4, and one other IMAP account, I experience ZD stopping to sync after a few minutes. When I try to display any email from any account, the following error message shows up:
- method: SearchConvRequest
- msg: Cannot connect to server.
- code: EMPTY_RESPONSE
It is not possible to do anything but closing the application ZimbraDesktop.
Any solution?

Logs
zdesktop.out:
STARTED Jetty Thu May 1 16:02:41 CST 2014
0 INFO [main] log - Logging to org.slf4j.impl.Log4jLoggerAdapter(org.mortbay.log) via org.mortbay.log.Slf4jLog
1697 INFO [main] log - jetty-6.1.22.z6
2211 INFO [main] log - No Transaction manager found - if your webapp requires one, please configure one.
Zimbra server process is running as uid=1000 euid=1000 gid=1000 egid=1000
Unable to determine platform because /mnt/Data/Mail/zdesktop/.platform does not exist.
Found SQLite NativeDb from Linux/i386
SQLite library version: 3.7.5
oldDbVersion=65 newDbVersion=65
oldOfflineDbVersion=5 newOfflineDbVersion=5
Unable to determine platform because /mnt/Data/Mail/zdesktop/.platform does not exist.
java.lang.OutOfMemoryError: Java heap space
Dumping heap to /mnt/Data/Mail/zdesktop/heapdump/java_pid12381.hprof ...
Exception in thread "sync-timer-dir" Heap dump file created [145260717 bytes in 22.584 secs]
java.lang.OutOfMemoryError: Java heap space
at java.lang.ClassLoader.findLoadedClass0(Native Method)
at java.lang.ClassLoader.findLoadedClass(Unknown Source)
at org.mortbay.jetty.webapp.WebAppClassLoader.loadCla ss(WebAppClassLoader.java:369)
at org.mortbay.jetty.webapp.WebAppClassLoader.loadCla ss(WebAppClassLoader.java:363)
at com.zimbra.cs.util.Zimbra.halt(Zimbra.java:391)
at com.zimbra.cs.account.offline.DirectorySync$1.run( DirectorySync.java:81)
at java.util.TimerThread.mainLoop(Unknown Source)
at java.util.TimerThread.run(Unknown Source)

zdesktop.log:
2014-05-01 16:08:01,247 FATAL [sync-mbox-xxx@yahoo.com] [] system - Out of memory
java.lang.OutOfMemoryError: Java heap space
at java.lang.StringCoding$StringDecoder.decode(Unknow n Source)
at java.lang.StringCoding.decode(Unknown Source)
at java.lang.String.<init>(Unknown Source)
at com.zimbra.common.zmime.ZInternetHeader.<init>(ZIn ternetHeader.java:76)
at com.zimbra.common.zmime.ZMimeParser.saveHeader(ZMi meParser.java:694)
at com.zimbra.common.zmime.ZMimeParser.handleByte(ZMi meParser.java:413)
at com.zimbra.common.zmime.ZMimeParser.handleBytes(ZM imeParser.java:368)
at com.zimbra.common.zmime.ZMimeParser.parse(ZMimePar ser.java:356)
at com.zimbra.common.zmime.ZMimeMessage.parse(ZMimeMe ssage.java:157)
at javax.mail.internet.MimeMessage.<init>(MimeMessage .java:209)
at com.zimbra.common.zmime.ZMimeMessage.<init>(ZMimeM essage.java:60)
at com.zimbra.cs.mime.Mime$FixedMimeMessage.<init>(Mi me.java:117)
at com.zimbra.cs.mime.ParsedMessage.init(ParsedMessag e.java:254)
at com.zimbra.cs.mime.ParsedMessage.initialize(Parsed Message.java:227)
at com.zimbra.cs.mime.ParsedMessage.initialize(Parsed Message.java:221)
at com.zimbra.cs.mime.ParsedMessage.<init>(ParsedMess age.java:166)
at com.zimbra.cs.datasource.MessageContent.getParsedM essage(MessageContent.java:60)
at com.zimbra.cs.datasource.imap.ImapFolderSync.handl eFetch(ImapFolderSync.java:917)
at com.zimbra.cs.datasource.imap.ImapFolderSync.acces s$200(ImapFolderSync.java:63)
at com.zimbra.cs.datasource.imap.ImapFolderSync$1.han dleFetchResponse(ImapFolderSync.java:827)
at com.zimbra.cs.mailclient.imap.FetchResponseHandler .handleResponse(FetchResponseHandler.java:32)
at com.zimbra.cs.mailclient.imap.ImapConnection.proce ssUntagged(ImapConnection.java:704)
at com.zimbra.cs.mailclient.imap.ImapConnection.proce ssResponse(ImapConnection.java:678)
at com.zimbra.cs.mailclient.imap.ImapConnection.waitF orResponse(ImapConnection.java:648)
at com.zimbra.cs.mailclient.imap.ImapConnection.sendR equest(ImapConnection.java:515)
at com.zimbra.cs.mailclient.imap.ImapRequest.send(Ima pRequest.java:95)
at com.zimbra.cs.mailclient.imap.ImapRequest.sendChec kStatus(ImapRequest.java:111)
at com.zimbra.cs.mailclient.imap.ImapConnection.uidFe tch(ImapConnection.java:331)
at com.zimbra.cs.datasource.imap.ImapFolderSync.fetch Messages(ImapFolderSync.java:843)
at com.zimbra.cs.datasource.imap.ImapFolderSync.fetch Messages(ImapFolderSync.java:750)
at com.zimbra.cs.datasource.imap.ImapFolderSync.syncM essages(ImapFolderSync.java:346)
at com.zimbra.cs.datasource.imap.ImapSync.syncMessage s(ImapSync.java:326)