MTA Transfers Mail Slowly or Stops and Event IDs 1294, 2253, 4284, 9156, and 9202 Appear (300445)

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256986 Description of the Microsoft Windows Registry

SYMPTOMS

After you upgrade your servers from Exchange Server version 4.0 Service Pack 4 to Exchange Server version 5.5, the message transfer agent (MTA) may process mail slowly over X.400 connectors or may even stop. The event log may display the following information about Event IDs 1294, 2253, 4284, 9156, and 9202:

Event ID: 1294
Source: MSExchangeMTA
Category: X.400 Service

Event ID: 2253
Source: MSExchangeMTA
Category: Directory Access

Event ID: 4284
Source: MSExchangeMTA
Category: X.400 Service

Event ID: 9156
Source: MSExchangeMTA
Category: Resource

Event ID: 9202
Source: MSExchangeMTA
Category: Warning

CAUSE

This behavior can occur if too few control blocks are available for the message transfer agent (MTA) to use to transfer messages over multiple X.400 connectors.

RESOLUTION

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Start Registry Editor (Regedt32.exe).
Locate the TCP/IP control blocks value under the following key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeMTA\Parameters
Edit the value of the TCP/IP control blocks so that it is equal to (10 * the number of X.400 connectors) + (number of sites).
Quit Registry Editor.
Quit and then restart the MTA service.