I receive the following error when trying to setup an account for the first time with Zimbra Desktop:

Code:
service.FAILURE: system failure: error while proxying request to target server: HTTP/1.0 503 Service Unavailable
Display error details
com.zimbra.common.soap.SoapFaultException: system failure: error while proxying request to target server: HTTP/1.0 503 Service Unavailable ExceptionId:com.zimbra.common.service.ServiceException: system failure: error while proxying request to target server: HTTP/1.0 503 Service Unavailable ExceptionId:btpool0-25:1308683113228:64b16baf777f58e4 Code:service.FAILURE at com.zimbra.common.service.ServiceException.FAILURE(ServiceException.java:248) at com.zimbra.cs.zclient.ZMailbox.invoke(ZMailbox.java:571) at com.zimbra.cs.zclient.ZMailbox.invoke(ZMailbox.java:555) at com.zimbra.cs.zclient.ZMailbox.invokeJaxb(ZMailbox.java:550) at com.zimbra.cs.zclient.ZMailbox.authByPassword(ZMailbox.java:496) at com.zimbra.cs.zclient.ZMailbox.(ZMailbox.java:411) at com.zimbra.cs.zclient.ZMailbox.getMailbox(ZMailbox.java:348) at com.zimbra.cs.account.offline.OfflineProvisioning.newZMailbox(OfflineProvisioning.java:224) at com.zimbra.cs.account.offline.OfflineProvisioning.newZMailbox(OfflineProvisioning.java:216) at com.zimbra.cs.account.offline.OfflineProvisioning.createSyncAccount(OfflineProvisioning.java:540) at com.zimbra.cs.account.offline.OfflineProvisioning.createAccount(OfflineProvisioning.java:513) at com.zimbra.cs.service.admin.CreateAccount.handle(CreateAccount.java:64) at com.zimbra.soap.SoapEngine.dispatchRequest(SoapEngine.java:412) at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.java:287) at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.java:158) at com.zimbra.soap.SoapServlet.doWork(SoapServlet.java:294) at com.zimbra.soap.SoapServlet.doPost(SoapServlet.java:215) at javax.servlet.http.HttpServlet.service(HttpServlet.java:725) at com.zimbra.cs.servlet.ZimbraServlet.service(ZimbraServlet.java:208) at javax.servlet.http.HttpServlet.service(HttpServlet.java:814) at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:390) at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:218) at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.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(HandlerWrapper.java:152) at org.mortbay.jetty.handler.rewrite.RewriteHandler.handle(RewriteHandler.java:230) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at org.mortbay.jetty.Server.handle(Server.java:326) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:543) at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:946) at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756) at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:405) at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410) at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:451) Caused by: com.zimbra.common.service.ServiceException: error while proxying request to target server: HTTP/1.0 503 Service Unavailable ExceptionId:btpool0-25:1308683113228:64b16baf777f58e4 Code:service.PROXY_ERROR Arg:(url, STR, "https://zimbra.multi-craft.net/service/soap/AuthRequest") at com.zimbra.common.service.ServiceException.PROXY_ERROR(ServiceException.java:313) at com.zimbra.common.soap.SoapHttpTransport.invoke(SoapHttpTransport.java:247) at com.zimbra.common.soap.SoapHttpTransport.invoke(SoapHttpTransport.java:164) at com.zimbra.common.soap.SoapTransport.invoke(SoapTransport.java:397) at com.zimbra.cs.zclient.ZMailbox.invoke(ZMailbox.java:561) ... 37 more Code:service.FAILURE at com.zimbra.common.soap.Soap12Protocol.soapFault(Soap12Protocol.java:88) at com.zimbra.common.soap.SoapTransport.extractBodyElement(SoapTransport.java:344) at com.zimbra.common.soap.SoapTransport.parseSoapResponse(SoapTransport.java:303) at com.zimbra.common.soap.SoapHttpTransport.invoke(SoapHttpTransport.java:260) at com.zimbra.common.soap.SoapHttpTransport.invoke(SoapHttpTransport.java:164) at com.zimbra.common.soap.SoapTransport.invoke(SoapTransport.java:397) at com.zimbra.common.soap.SoapTransport.invoke(SoapTransport.java:360) at com.zimbra.cs.account.soap.SoapProvisioning.invoke(SoapProvisioning.java:321) at com.zimbra.cs.account.soap.SoapProvisioning.createAccount(SoapProvisioning.java:464) at com.zimbra.cs.offline.jsp.JspProvStub.createOfflineAccount(JspProvStub.java:94) at com.zimbra.cs.offline.jsp.ZmailBean.doRequest(ZmailBean.java:102) at com.zimbra.cs.offline.jsp.FormBean.doRequest(FormBean.java:150) at sun.reflect.GeneratedMethodAccessor33.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.sun.el.parser.AstFunction.getValue(AstFunction.java:127) at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:206) at org.apache.jasper.runtime.PageContextImpl.evaluateExpression(PageContextImpl.java:1001) at org.apache.jsp.desktop.accsetup_jsp._jspx_meth_c_when_6(Unknown Source) at org.apache.jsp.desktop.accsetup_jsp._jspx_meth_c_choose_0(Unknown Source) at org.apache.jsp.desktop.accsetup_jsp._jspService(Unknown Source) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:109) at javax.servlet.http.HttpServlet.service(HttpServlet.java:814) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:389) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:486) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:380) at javax.servlet.http.HttpServlet.service(HttpServlet.java:814) at com.zimbra.webClient.servlet.JspServlet.service(JspServlet.java:64) at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) at com.zimbra.cs.servlet.SetHeaderFilter.doFilter(SetHeaderFilter.java:79) at com.zimbra.webClient.filters.SetHeaderFilter.doFilter(SetHeaderFilter.java:239) at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:218) at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.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(HandlerWrapper.java:152) at org.mortbay.jetty.handler.rewrite.RewriteHandler.handle(RewriteHandler.java:230) at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) at org.mortbay.jetty.Server.handle(Server.java:326) at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:543) at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:946) at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756) at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:405) at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410) at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:451)

This is a new installation of Zimbra, and the Web Client works fine.