Mail sent using CDOSYS fails after installing hotfix from KB 2141007
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Applies to: Microsoft Windows Server 2003 Service Pack 2
On Microsoft Windows Server 2003 or 2003 R2, sending an email by SMTP port with CDOSYS and using NTLM fails after installing the hotfix from KB 2141007. It fails with authentication and typically you receive an error message "5.7.3 Client was not authenticated" from the SMTP server.
KB 2141007 updates inetcomm.dll and this affects the behavior of cdosys.dll. After this hotfix is installed, you must update custom code that uses CDOSYS so that it uses the pickup folder instead of a local SMTP server.
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
313773 How to send e-mail messages by using CDOSYS and the local SMTP directory with Visual Basic .NET