"Probable Cause: The specified computer is off-line or network problems are preventing communication Error Code: 0x80004005 Error Message: LDAP Error 0x51 occurred"
These errors indicate that either the Exchange LDAP is configured to use a different port number other than the default port of 389, LDAP is disabled, or the Exchange Server is not online.
Refer to the following Microsoft articles for more information regarding LDAP errors:
- Article ID 218185 - Microsoft LDAP Error Codes: http://support.microsoft.com/kb/q218185 - From MSDN Library: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ldap/ldap/return_values.asp
Also confirm the following:
1. Confirm the LDAP Port number and that LDAP is enabled in this Exchange Site. If the LDAP port number is not 389, then this needs to be reflected for the Exchange Servers Properties in the MessageStats Console.
If the Exchange 5.5 Server is installed on a Windows 2000 Domain Controller then the default LDAP Port #389 must be changed to another number because Active Directory uses port 389 for LDAP, and it doesnt share this port with Exchange 5.5.
Refer to the following Microsoft articles for more information:
- Article ID 240078 - "Exchange Server and Active Directory Utilize the same LDAP Ports": http://support.microsoft.com/default.aspx?scid=kb;en-us;240078 - Article ID 312501 - "HOW TO: Change the LDAP Port for Exchange Server 5.5 in Exchange Server 5.5": http://support.microsoft.com/default.aspx?scid=kb;en-us;312501
2. The result code LDAP_SERVER_DOWN indicates that the LDAP SDK for C cannot establish a connection with, or lost the connection to the LDAP server. If you have not established an initial connection with the server, verify that you have specified the correct host name and port number and that the server is running. If you have lost the connection to the server, refer to "Handling Failover": http://docs.sun.com/source/817-6707/using.html#wp28869, of Chapter 4, "Using the LDAP API" for instructions on reconnecting to the server.
#define LDAP_SERVER_DOWN 0x51 /* 81 */
Verify the DNS settings are correct for that server.
3. Run Microsoft�s LDP support tool, which can be found in the support tools folder on either the Windows 2000 Server or the Windows 2003 Server CD, to try connecting to the Exchange Server. (MessageStats functions pretty much the same as that tool, with regards to LDAP connections.)