SMTP: Err Msg: ERROR Connect: (121) Network Error (99852)


The information in this article applies to:

  • Microsoft Mail Gateway to SMTP 2.1
  • Microsoft Mail Gateway to SMTP 3.0
This article was previously published under Q99852

SYMPTOMS

Versions 2.1 and 3.0 of Microsoft Mail Gateway to SMTP may display one of the following messages:

  • ERROR connect: (121) network error

    -or-

  • ERROR connection to smart host failed

    -or-

  • NC_incoming: unavailable
These errors indicate that the SMTP Gateway cannot connect to the SMTP router, also called the smarthost, which you can configure in the Administrator program under Gateway, SMTP, Setup, as follows: 
   IP address of SMTP Router:  XXX.XXX.XXX.XXX

CAUSE

The error occurs if:

  • The smarthost is down.
  • The smarthost is not configured to answer SMTP calls.
  • The network between the SMTP gateway computer and the smarthost is down.
  • The TCP/IP configuration on the gateway computer is incorrect.

RESOLUTION

You can test for the above conditions by trying to "telnet" to port 25 of the SMTP router: type the number 25 after the IP address of your SMTP router. If this test succeeds, the gateway will run. If it fails, you have to bring the host or network back up, or make configuration changes as needed.

The telnet process may differ with software. Consult the telnet documentation for a particular port connection procedure.
Modification Type:MajorLast Reviewed:2/24/2004
Keywords:KB99852
©2004 Microsoft Corporation. All rights reserved.