My both server SRV1, SRV2 running MSExchange 5.5 on Windows 2000 Server. They are in the same domain. SRV2 receive this Warning in Event Viewer each 11 minutes. Event Type: Warning Event Source: MSExchangeMTA Event Category: Interface Event ID: 9318 Date: 3/17/2004 Time: 5:01:16 PM User: N/A Computer: EVNSRV45 Description: An RPC communications error occurred. Unable to bind over RPC. Locality Table (LTAB) index: 183, NT/MTA error code: 1722. Comms error 1722, Bind error 1722, Remote Server Name SRV1 [MAIN BASE 1 500 %10] (14) This is the chart of my company: Internet -----> SRV2 -----> SRV1 -----> users. The users cannot receive mails from Internet. Any suggestion is appreciated. Help me please. Ha.