郵件發送失敗( connection failed，Can't send command to SMTP host，Broken pipe)

問題：用JAVA MAIL發送郵件的時候報以下錯誤：

Mail server connection failed; nested expection is javax.MessagingException:

Can't send command to SMTP host;
nested exception is:
  java.net.SocketException:

Write failed: Broken pipe

解決：經search一番，發現最終的原因是抄送給了自己導致的，即from跟cc或bcc中的某個郵箱地址是一樣．