When sending an email, exceptions may occur: failed to access the "CDO. Message" object.

Sort out several cases that may cause exceptions in the cocould not access 'cdo. message' object, which are comprehensive, but not omnipotent...

1. No permission:
For details, see:
Http://blog.joycode.com/ghj/archive/2004/02/17/13197.aspx

2. The FAQ of system. Web. Mail provides six other cases. I will not resend them and check them myself.
Http://www.systemwebmail.com/faq/4.2.3.aspx

3. You have installed anti-virus software or a firewall,
Taking McAfee VirusScan Enterprise 8.0 as an example, in Port restrictions, the division of partitions is restricted by default,
Success,
TheseProgramPort 25. Port 25 is used for SMTP. At this time, an error will be reported that the "CDO. Message" object cannot be accessed. You only need to put your program name in the exception list to bypass this restriction. For example:
 

4. If your mail server has poor performance, times out frequently, or other errors, it will also report the error of failing to access the "CDO. Message" object.