TRY again errors when sending email..

On occasion, users will receive 'An unknown error (mail.TRY_AGAIN) has occurred. on their web client... Below is the log info:+

2011-06-27 18:34:25,823 INFO [btpool0-42239://email.domain.com/service/soap/GetMsgRequest] [name=vanessa.lucero@domain.com;mid=731;ip=10.1.10. 60;ua=ZimbraWebClient - IE6 (Win)/6.0.7_GA_2470.RHEL5_64;] soap - GetMsgRequest
2011-06-27 18:34:26,098 INFO [btpool0-42245://email.domain.com/service/soap/SendMsgRequest] [name=wilburn.anderson@domain.com;mid=1275;ip=10.1. 10.60;ua=ZimbraWebClient - IE8 (Win)/6.0.7_GA_2470.RHEL5_64;] SoapEngine - handler exception
com.zimbra.cs.mailbox.MailServiceException: try again: message send already in progress: 1309213939546
ExceptionId:btpool0-42245://email.domain.com/service/soap/SendMsgRequest:1309214066098:dbcbf865b1c8f93c
Code:mail.TRY_AGAIN
at com.zimbra.cs.mailbox.MailServiceException.TRY_AGA IN(MailServiceException.java:471)


The server doesnt seem to be under any exceptional load at this time. Our configuration for 4000 users is as follows:


proxy server
2 mailstores 16gb ram each 15k fiber drives 10 spindles raid5 for stores
2 LDAP servers
1 archive

These are under vsphere 4.x Mailstores have 2 dedicated cores each, and hover around a load of 2.x with about 1200 web clients active per server at a time

I have noticed every once in a while a 'please wait while contacting server' message in the middle of email.. its rare, however. I have followed the tuning guidelines fairly well.

Im noticing my cpu wait time right now moving from 2-3 percent up to 40+ percent. .. with an average right around 15% wait.

Does anyone have any idea about this? Im getting a ton of issues with autocompleting gal lookups as well. I put a support ticket in YESTERDAY at sev-2 and have gotten no response. I have managed to tweak vmware settings and TCP settings as much as possible and have lowered the system's load and network processes significantly.. There isnt much more tweaking I can do - but zimbra is still behaving badly..

An unknown error (mail.TRY_AGAIN) has occurred.
method: [unknown]
msg: try again: Unable to connect to the MTA
code: mail.TRY_AGAIN
detail: soap:Receiver
trace: com.zimbra.cs.mailbox.MailServiceException: try again: Unable to connect to the MTA ExceptionId:btpool0-9://mobilessl.com/service/soap/SendMsgRequest:1310663347040:a7659ab727fc7cf6 Code:mail.TRY_AGAIN at com.zimbra.cs.mailbox.MailServiceException.TRY_AGA IN(MailServiceException.java:479) at com.zimbra.cs.mailbox.MailSender.sendMimeMessage(M ailSender.java:628) at com.zimbra.cs.mailbox.MailSender.sendMimeMessage(M ailSender.java:425) at com.zimbra.cs.mailbox.MailSender.sendMimeMessage(M ailSender.java:385) at com.zimbra.cs.service.mail.SendMsg.doSendMessage(S endMsg.java:193) at com.zimbra.cs.service.mail.SendMsg.handle(SendMsg. java:154) at com.zimbra.soap.SoapEngine.dispatchRequest(SoapEng ine.java:412) at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.jav a:287) at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.jav a:158) at com.zimbra.soap.SoapServlet.doWork(SoapServlet.jav a:294) at com.zimbra.soap.SoapServlet.doPost(SoapServlet.jav a:215) at javax.servlet.http.HttpServlet.service(HttpServlet .java:725) at com.zimbra.cs.servlet.ZimbraServlet.service(Zimbra Servlet.java:208) at javax.servlet.http.HttpServlet.service(HttpServlet .java:814) at org.mortbay.jetty.servlet.ServletHolder.handle(Ser vletHolder.java:511) at org.mortbay.jetty.servlet.ServletHandler$CachedCha in.doFilter(ServletHandler.java:1166) at com.zimbra.cs.servlet.SetHeaderFilter.doFilter(Set HeaderFilter.java:79) at org.mortbay.jetty.servlet.ServletHandler$CachedCha in.doFilter(ServletHandler.java:1157) at org.mortbay.servlet.UserAgentFilter.doFilter(UserA gentFilter.java:81) at org.mortbay.servlet.GzipFilter.doFilter(GzipFilter .java:132) at org.mortbay.jetty.servlet.ServletHandler$CachedCha in.doFilter(ServletHandler.java:1157) at org.mortbay.jetty.servlet.ServletHandler.handle(Se rvletHandler.java:388) at org.mortbay.jetty.security.SecurityHandler.handle( SecurityHandler.java:218) at org.mortbay.jetty.servlet.SessionHandler.handle(Se ssionHandler.java:182) at org.mortbay.jetty.handler.ContextHandler.handle(Co ntextHandler.java:765) at org.mortbay.jetty.webapp.WebAppContext.handle(WebA ppContext.java:422) at org.mortbay.jetty.handler.ContextHandlerCollection .handle(ContextHandlerCollection.java:230) at org.mortbay.jetty.handler.HandlerCollection.handle (HandlerCollection.java:114) at org.mortbay.jetty.handler.HandlerWrapper.handle(Ha ndlerWrapper.java:152) at org.mortbay.jetty.handler.rewrite.RewriteHandler.h andle(RewriteHandler.java:230) at org.mortbay.jetty.handler.HandlerWrapper.handle(Ha ndlerWrapper.java:152) at org.mortbay.jetty.handler.DebugHandler.handle(Debu gHandler.java:77) at org.mortbay.jetty.handler.HandlerWrapper.handle(Ha ndlerWrapper.java:152) at org.mortbay.jetty.Server.handle(Server.java:326) at org.mortbay.jetty.HttpConnection.handleRequest(Htt pConnection.java:543) at org.mortbay.jetty.HttpConnection$RequestHandler.co ntent(HttpConnection.java:946) at org.mortbay.jetty.HttpParser.parseNext(HttpParser. java:756) at org.mortbay.jetty.HttpParser.parseAvailable(HttpPa rser.java:218) at org.mortbay.jetty.HttpConnection.handle(HttpConnec tion.java:405) at org.mortbay.io.nio.SelectChannelEndPoint.run(Selec tChannelEndPoint.java:410) at org.mortbay.thread.BoundedThreadPool$PoolThread.ru n(BoundedThreadPool.java:451) Caused by: java.net.UnknownHostException: nospam@mobilessl.com at java.net.PlainSocketImpl.connect(PlainSocketImpl.j ava:195) at java.net.SocksSocketImpl.connect(SocksSocketImpl.j ava:366) at java.net.Socket.connect(Socket.java:529) at com.zimbra.cs.mailclient.MailConnection.newSocket( MailConnection.java:416) at com.zimbra.cs.mailclient.MailConnection.connect(Ma ilConnection.java:74) at com.zimbra.cs.mailclient.smtp.SmtpTransport.protoc olConnect(SmtpTransport.java:180) at javax.mail.Service.connect(Service.java:291) at javax.mail.Service.connect(Service.java:172) at javax.mail.Service.connect(Service.java:121) at com.zimbra.cs.mailbox.MailSender.sendMessageToHost (MailSender.java:894) at com.zimbra.cs.mailbox.MailSender.sendMessage(MailS ender.java:831) at com.zimbra.cs.mailbox.MailSender.sendMimeMessage(M ailSender.java:565) ... 39 more
request:

Body: {
SendMsgRequest: {
_jsns: "urn:zimbraMail",
m: {
e: [
0: {
a: "admin@mobilessl.com",
add: "0",
p: "admin",
t: "t"
},
1: {
a: "admin@mobilessl.com",
add: "0",
p: "admin",
t: "c"
},
2: {
a: "mega@mobilessl.com",
p: "Iin mrs. Ningtias",
t: "f"
}
],
idnt: "917a7eb1-269e-4805-a095-a852bdadb213",
mp: [
0: {
content: {
_content: "hallo., word"
},
ct: "text/plain"
}
],
su: {
_content: "tes"
}
},
suid: 1310663345503
}
},
Header: {
context: {
_jsns: "urn:zimbra",
account: {
_content: "mega@mobilessl.com",
by: "name"
},
authToken: "(removed)",
session: {
_content: 12,
id: 12
},
userAgent: {
name: "ZimbraWebClient - FF3.0 (Linux)",
version: "7.1.1_GA_3196"
}
}
}

I got the same error with 7.1.2.

Has anyone solved this problem?

is it correct that everything is working except sending mails?

if so, I had the same problem after upgrading to 7.1.4.
please try this:

is there a file transport.db??
####################
dir /opt/zimbra/postfix/conf/transport.db
no such file or directory
####################

if not, do this and everything is fine:

####################
makemap -N hash /opt/zimbra/postfix/conf/transport < /opt/zimbra/postfix/conf/transport
####################

cheers
christopher