I am posting the error message here, please let me know how to resolve this:

Debug message: error while proxying request to target server The server mail8.homesteadmail.com failed to respond

Exception:

com.zimbra.common.soap.SoapFaultException: error while proxying request to target server The server mail8.homesteadmail.com failed to respond
ExceptionId:btpool0-694:1313758516418:175a379519839c5e
Code:service.PROXY_ERROR
at com.zimbra.common.soap.Soap12Protocol.soapFault(So ap12Protocol.java:88)
at com.zimbra.common.soap.SoapTransport.extractBodyEl ement(SoapTransport.java:266)
at com.zimbra.common.soap.SoapTransport.parseSoapResp onse(SoapTransport.java:227)
at com.zimbra.common.soap.SoapHttpTransport.invoke(So apHttpTransport.java:295)
at com.zimbra.common.soap.SoapHttpTransport.invoke(So apHttpTransport.java:230)
at com.zimbra.common.soap.SoapTransport.invoke(SoapTr ansport.java:318)
at com.zimbra.common.soap.SoapTransport.invokeWithout Session(SoapTransport.java:305)
at com.zimbra.cs.mailbox.OfflineMailbox.sendRequest(O fflineMailbox.java:776)
at com.zimbra.cs.mailbox.OfflineMailbox.sendRequest(O fflineMailbox.java:740)
at com.zimbra.cs.mailbox.OfflineMailbox.sendRequest(O fflineMailbox.java:736)
at com.zimbra.cs.mailbox.OfflineMailbox.sendRequest(O fflineMailbox.java:732)
at com.zimbra.cs.mailbox.OfflineMailbox.sendRequest(O fflineMailbox.java:728)
at com.zimbra.cs.mailbox.DeltaSync.sync(DeltaSync.jav a:88)
at com.zimbra.cs.mailbox.DeltaSync.sync(DeltaSync.jav a:76)
at com.zimbra.cs.mailbox.MailboxSync.sync(MailboxSync .java:188)
at com.zimbra.cs.mailbox.OfflineMailbox.sync(OfflineM ailbox.java:140)
at com.zimbra.cs.service.offline.OfflineSync.handle(O fflineSync.java:47)
at com.zimbra.soap.SoapEngine.dispatchRequest(SoapEng ine.java:429)
at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.jav a:286)
at com.zimbra.soap.SoapEngine.dispatch(SoapEngine.jav a:160)
at com.zimbra.soap.SoapServlet.doPost(SoapServlet.jav a:275)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:727)
at com.zimbra.cs.servlet.ZimbraServlet.service(Zimbra Servlet.java:187)
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.handle(Se rvletHandler.java:362)
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)

If issue persists please post description and debug information here.