Do you know why MAPI is not suitable for HTML messages?
MAPI 1.0 was written before HTML mail was developed and does not reliably support the creation of HTML-formatted messages. As you know, MAPI 1.0 is the version supported by all versions of Microsoft Exchange through version 5.5 (and all Service Packs). This includes the following subordinate technologies:
•Active Messaging (Collaboration Data Objects (CDO) 1.1)
•CDO versions 1.2 and 1.21
•MAPI controls (Msmapi32.ocx)
Extended Messaging Application Programming Interface (MAPI) should not be used to generate HTML-formatted messages.
What is needed?
If messages are needed in HTML format, such as for sending text formatted in other languages, alternative technologies that provide more reliable support for HTML messages are recommended:
•CDO for Windows 2000 (CDOSYS)
•CDO for Exchange 2000 (CDOEX)
•Outlook Object Model of Microsoft Outlook 98 or later
•SMTP-capable ActiveX controls obtained from third-party vendors
In short, as an alternative, we should consider using the Microsoft Outlook Object Model, CDONTS, CDOSYS, CDOEX, or a third-party SMTP control.