Exchange 2010 Inbound SMTP mail | 421 4.4.1 Connection timed out

狀況：
Exchange 2010無法收 mail，用 telnet mail.company.com 25 測試，敲完 helo 就出現 421 4.4.1 Connection timed out

解法：Exchange 2010 Inbound SMTP mail | 421 4.4.1 Connection timed out

1. restart service "MSExchangeTransport"

2. 將啟動模式改為 "Automatic (Delayed Start)"