定时调度发送邮件失败，请问这是什么原因

百度也没找到合适的解决方案，错误原因代码如下：

com.sun.mail.util.MailConnectException: Couldn't connect to host, port: localhost, 25; timeout -1;

nested exception is:

java.net.ConnectException: Connection refused: connect

at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2209)

at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:740)

at javax.mail.Service.connect(Service.java:366)

at javax.mail.Service.connect(Service.java:246)

at com.fr.base.EmailManager.connect(Unknown Source)

at com.fr.base.EmailManager.sendEmail(Unknown Source)

at com.fr.base.EmailManager.send(Unknown Source)

at com.fr.base.EmailManager.sendWithRecord(Unknown Source)

at com.fr.base.EmailManager.send(Unknown Source)

at com.fr.base.EmailManager.sendTestMail(Unknown Source)

at com.fr.decision.webservice.v10.config.ConfigService.testEmailConnection(Unknown Source)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at com.fr.decision.config.ConfigInterceptor.intercept(Unknown Source)

at com.fr.decision.webservice.v10.config.ConfigService$$EnhancerByCGLIB$$fb9e39a3.testEmailConnection(<generated>)

at com.fr.web.controller.decision.api.config.EmailResource.testEmail(Unknown Source)

at com.fr.web.controller.decision.api.config.EmailResource$$FastClassBySpringCGLIB$$6124e2a1.invoke(<generated>)

at com.fr.third.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:201)

at com.fr.third.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:710)

at com.fr.third.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)

at com.fr.third.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:85)

at com.fr.decision.webservice.aspect.DecisionLogAspect.doControllerAround(Unknown Source)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at com.fr.third.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:621)

at com.fr.third.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:610)

at com.fr.third.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:69)

at com.fr.third.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:168)

at com.fr.third.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)

at com.fr.third.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)

at com.fr.third.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:646)

at com.fr.web.controller.decision.api.config.EmailResource$$EnhancerBySpringCGLIB$$14dfb0a8.testEmail(<generated>)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at com.fr.third.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)

at com.fr.third.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)

at com.fr.third.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)

at com.fr.third.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:747)

at com.fr.third.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:676)

at com.fr.third.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)

at com.fr.third.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)

at com.fr.third.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)

at com.fr.third.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)

at com.fr.third.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:652)

at com.fr.third.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)