我正在使用JavaMail从gmail帐户读取java电子邮件。代码在我的Windows 7机器上工作得很好。但是，在Windows 2k8计算机上运行后，相同的代码错误（下面提到的是错误）。代码绝对没有变化。 有人可以帮助了解这次失败的原因吗？
错误：
javax.mail.MessagingException: Connection timed out: connect;
nested exception is:
java.net.ConnectException: Connection timed out: connect
at com.sun.mail.imap.IMAPStore.protocolConnect(IMAPStore.java:618)
at javax.mail.Service.connect(Service.java:291)
at javax.mail.Service.connect(Service.java:172)
at com.vmware.cmpaas.uiqe.util.EmailUtil.getActivationLink(EmailUtil.java:42)
at Temp_Test.main(Temp_Test.java:17)
Caused by: java.net.ConnectException: Connection timed out: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at sun.security.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:618)
at sun.security.ssl.BaseSSLSocketImpl.connect(BaseSSLSocketImpl.java:160)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:284)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:227)
at com.sun.mail.iap.Protocol.<init>(Protocol.java:109)
at com.sun.mail.imap.protocol.IMAPProtocol.<init>(IMAPProtocol.java:104)
at com.sun.mail.imap.IMAPStore.protocolConnect(IMAPStore.java:585)
... 4 more
Exception in thread "main" java.lang.NullPointerException
at Temp_Test.main(Temp_Test.java:18)