I have a Zimbra Open Source 5.0.1_GA install on Rhel 5 server and everything was working before. It was not in use for sending/receiving emails for a couple of months, but today suddenly while sending emails, I receive a 'Network service error' and emails do not go, it seems to time out.

All services are running, I am using a browser on the Zimbra mail server itself (to rule out network latency), DNS forward and reverse lookup entries are resolving correctly. I can login to the Zimbra collabration suite without issues, but cannot send emails.

I know there have been a few posts on this, but none of them have helped my scenario. The firewall is disabled and so is selinux. There is no other mailing service from Rhel running. This was running fine a few months back and no changes have been made.

Have been struggling with this for a long time now, any help will be really appreciated.

Here is the output from /opt/zimbra/log/mailbox.log:


2008-10-01 13:02:06,663 INFO [btpool0-8] [name=admin@licsdc.com;mid=2;ua=zclient/5.0.1_GA_1902.RHEL5;SoapEngine - handler exception
com.zimbra.common.service.ServiceException: system failure: MessagingException
Code:service.FAILURE
at com.zimbra.common.service.ServiceException.FAILURE (ServiceException.java:183)
at com.zimbra.cs.mailbox.MailSender.sendMimeMessage(M ailSender.java:315)
at com.zimbra.cs.mailbox.MailSender.sendMimeMessage(M ailSender.java:115)
at com.zimbra.cs.service.mail.SendMsg.doSendMessage(S endMsg.java:185)
at com.zimbra.cs.service.mail.SendMsg.handle(SendMsg. java:150)
at com.zimbra.soap.SoapEngine.dispatchRequest(SoapEng ine.java:342)
at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.jav a:208)
at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.jav a:113)
at com.zimbra.soap.SoapServlet.doPost(SoapServlet.jav a:272)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:727)
at com.zimbra.cs.servlet.ZimbraServlet.service(Zimbra Servlet.java:174)
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$CachedCha in.doFilter(ServletHandler.java:1093)
at org.mortbay.servlet.UserAgentFilter.doFilter(UserA gentFilter.java:81)
at org.mortbay.servlet.GzipFilter.doFilter(GzipFilter .java:148)
at org.mortbay.jetty.servlet.ServletHandler$CachedCha in.doFilter(ServletHandler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle(Se rvletHandler.java:360)
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.cs.mailbox.MailSender$SafeMessagingExce ption: Read timed out; chained exception is:
java.net.SocketTimeoutException: Read timed out
at com.sun.mail.smtp.SMTPTransport.readServerResponse (SMTPTransport.java:1598)
at com.sun.mail.smtp.SMTPTransport.close(SMTPTranspor t.java:685)
at javax.mail.Transport.send0(Transport.java:171)
at javax.mail.Transport.send(Transport.java:98)
at com.zimbra.cs.mailbox.MailSender.sendMessage(MailS ender.java:428)
at com.zimbra.cs.mailbox.MailSender.sendMimeMessage(M ailSender.java:248)